Naval gunnery 1890 to 1945 and lessons drawn

 

Naval gunnery was in a dismal shape during the last decade of the 19th century. The old extremely smoke-producing blackpowder (not really a "powder" any more at that time) propellants had recently been replaced by smokeless propellants (such as the hazardous cordite in the Royal Navy) and breech-loaded guns were being adopted for good, but the gunnery and artillery ship design was in a horrible state of affairs.

Expected useful firing ranges were short (less than 4 km against ships), as optical range-finding was in its infancy and there was no central fire control yet. The coal-fired boilers produced terrible amounts of smoke and many guns were placed so low even on battleships that fairly normal rough seas made them temporarily unusable as waves crashed into them.

The typical armament of an armoured ship of the time consisted of two or four large calibre guns (8"...13.5" calibre), with a substantial secondary battery of  usually 4...6" calibre and soon some smaller guns specifically to shoot at the small (about 200 tons) and nimble torpedo boats.

There was a break in rate of fire between 6" guns and heavier guns because 6" has the heaviest shells that can be loaded by hand throughout a long battle by the non-roided men of the 1890...1945 period. The heavier guns used more machinery to load shell and propellant and this was slower, not faster (and still is, though it's faster than manual loading for the modern naval guns of up to 130 mm).

This huge drop in rate of fire from about 5...15 rpm for 5...6" guns to 1.5...3 rpm for most heavier guns was in part cushioned by the reality of long-range gunnery post-1910, but this rate of fire and the huge cost, size and mass increase past 6" calibre led to a curious situation at first:

Ever since the 1860's there were many warships with a primary artillery of few impressive big turret guns and many more smaller and somewhat hidden casemate guns up to 6". The public perceived the primary guns as the defining firepower. Those guns may have penetrated heavy armour protection on other ships, while the smaller guns did not. The reality was almost certainly known to most warship-commanding naval officers and naval gunnery officers: The secondary guns were the main armament and the big guns were for show and possibly useful in coastal bombardment, or as a deterrence.

The small guns fired so much more often that they were bound to score about tenfold as many hits at the then-relevant combat ranges. The heavy guns fired so rarely that corrections after observation of fall of shot by the gunner were obsolete by the time the heavy guns were ready to fire again.

Smaller than 8" shells were also less likely to be duds when they hit some unarmoured part of a ship where a very large calibre shell fuses often failed to trigger even as late as during the Second World War.

Royal Sovereign (1891) 13.5" twin barbette

A most egregious example was the Royal Sovereign class, which had four 13.5" guns in twin barbette mounts. Those were unarmoured to save mass high up on the ship, to improve rolling behaviour and general seakeeping. (The ships of this class still rolled badly when introduced.)

These 13.5" guns fired one broadside salvo every 135 seconds only, (0.44 rpm), as they could only be reloaded in fore-and-aft position. They might not have fired more than four or five shots per barrel in a battle, for the unprotected crew would likely have been cut down by fragmentation and even shrapnel (that was still a thing in navies at the time and has recently kind of returned with the 35 mm Millennium gun and its AHEAD munition) by many small calibre hits at that point. Meanwhile, the Royal Sovereign's protected 6" gun crews could have continued the fight with 25 or more rpm in total (port or starboard).

You may think that those 6" shells wouldn't do much damage, but most parts of any warship were unprotected or at most protected against fragments and shrapnel. Fires could be started (there was still much flammable material and even oil lamps in use) and the heat and smoke could render the burning ship combat ineffective (secondary fires could even doom it).

Most direct damage done - even by hits of the heaviest calibres -  would still usually be superficial, as the shells up to the First World War period usually used impact fuses without the delay required for explosions where they hurt the most (boiler rooms, turbine rooms, magazines deep inside the  hull). Secondary explosions were rather flash fires in turrets or where turrets and their munition hoists if not magazines were very close to the side of the hull. The extremely delicate boiler rooms with all their pressurized containers and pipes were so rarely harmed that even badly-hurt ships could make it to home port if not finished off by a magazine explosion or torpedo hit.

A bit more about rate of fires; by the Second World War, these had been improved to maximum slightly more than 3 rpm for (German) 15" guns, about 15 rpm for some (American) 6" guns, about 20 rpm for (American) 5" guns and also for 4" guns. Army 3" guns had reached about 30 rpm before 1900 already, but many early naval 3" mounts fell well short of such  rate of fire. The practical rates of fire on a warship in a gunfight were mostly MUCH slower.

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Let's pause with this military technology history wonkery and look at a still-relevant lesson:

The public was very much fascinated by and interested in its battlefleet (at least the middle and upper classes, especially in urban areas). Such huge armoured ships did cost a fortune each, and were a heavy fiscal burden even to the richest countries. Yet all this attention did not reveal the terrible flaws of the capital ships of the period, much less lead to civilian oversight pressure to work on those deficiencies. That push came largely from some high-ranking officers who especially in the Royal Navy thought the time was due to become an actual fighting force again. (The newcomer German navy had been in technology catchup and modernisation mode anyway and no such awakening experience.)

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Thus improvements were made after the Royal Sovereigns; later capital ship primary artillery always had properly-protected turrets (many gun crews in the 4"...6" gun range especially on cruisers remained inadequately protected even against fragmentation), and a long time after (after the First World War) the last navies adopted proper and high-enough mounted secondary artillery turrets instead of casemates. There were also experiments with really high-mounted casemates in the superstructure. 

The biggest change happened with regard to fire control and quantity of the primary artillery guns. The individual aiming was hopeless at long ranges, and thus fire control became centralized with gunners in turrets merely following orders about elevation and training as well as shooting the guns.

It was understood that simply giving more gunnery practise did not suffice; you needed to observe the fall of shot and correct accordingly. This required salvo fire and all guns aiming the same (or, if spaced much, at least using the same gun elevation). A mast top-located observer would see whether the water fountains were too far left, right, long or short and issue corrections. Eventually, the salvoes would straddle the target (shells impacting on or around the target) and the salvoes would continue without further corrections at highest possible rate of fire until the salvoes were observed to be off again or the target turned.

Mechanical fire control computing aids were introduced, communication devices were needed between fire control and turrets and optical rangefinders were introduced and improved until they could in theory measure distances to the horizon. Such (except the computers) was the art of gunnery by the First World War. This centralised aiming and firing depended so much on observation of the fall of salvoes that a rule of thumb began to dominate warship design; it took a salvo of at least six shots for a proper observation, and the guns better not be spaced very much (this led to a few capital ships with all primary artillery on the forecastle; Nelson, Rodney, Strasbourg, Dunkerque, Richelieu, Jean Bart). Some capital ships had 12 primary artillery guns and were able to shoot at two different targets with full fire control process simultaneously. This helped alleviate the issue of long spacing between turrets. Many dreadnoughts and super dreadnoughts were on the other hand unable to fire with a full 6 shell salvo in (nearly) all directions, although this had already been achieved with HMS Dreadnought (and the prototype battlecruiser HMS Invincible shortly after). They were thus rather a kind of ship of the line, optimised for broadsides only.

The so-called Pre-Dreadnought battleships with their mere two or four primary artillery guns were thus obsolete with the rise of centralised aiming and firing, and the appearance of HMS Dreadnought in 1906 is commonly considered to be the signal for this paradigm change. 

Finally, by about 1910 there was no reasonable doubt any more that the primary artillery was actually the main armament of battleships. The other guns turned into self-defence weapons until battleships were turned into heavy (anti-air) escorts by the rise of the aircraft carrier in 1942 (then the secondary or even tertiary guns in the 40 mm...133 mm range became the main weapons).

Now back to why large calibre gun rates of fire weren't THAT terrible during the World Wars as it seemed (despite shooting even more slowly in practice than nominally able to): The cycle of flight of shot, observing, reporting, calculating, transmitting directions to turrets, turrets training and elevating according to directions and finally firing a salvo together took longer than the reload even of a 16" gun. Practical rates of fire were even much worse than nominal ones. The Bismarck was capable of shooting its 38 cm (~15") guns in 18 second intervals. That should have sufficed for about 45 salvoes in its battle with HMS Hood and HMS Prince of Wales. It fired off 13 salvoes only.

The nominal rate of fire was really only important at short ranges that required no observation and corrections, such as night combat at ranges of less than 4 km. Such ranges also devalued armour very much; horizontal armour would not be tested and vertical (belt) armour would be more easily penetrated as it was meant to protect at a greater distance only. This quick fire superiority scenario of a short range night battle allowed the really quick-firing American 6" guns to shine in the Guadalcanal campaign. Even the Japanese battlecruisers were inadequately protected against 6" shells due to their narrow belt armour.

(Now keep in mind that a ship such as the HMS Royal Sovereign of the 1890's would have made full use of its rate of fire, for it would not have the shoot-observe-correct fire control cycle. It would have made full use of 2 rpm rate of fire if it had had such a rate of fire. Its 0.44 rpm broadside rate of fire was thus exactly as bad as it sounds. The 2 rpm of some First World War-era main guns was not as bad, as the fire control process slowed them to less than 2 rpm during most of the battle anyway.)

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Fast forward to the Second World War period: What was the peak of warship gun duel gunnery then?

The peak in daytime would have been like this: An aircraft or small and nimble escorting destroyers would lay a smoke concealment to blind the enemy fire controllers (see excellent collection of photos here). 

The own ship would use its radar and fire control computer for a first salvo or set of bracket salvoes, and a spotter (float)plane would issue the corrections by radio instead of the ship's own observers in mast tops. Top quality radars could even detect the impact slashes of big shells and shells had dyes of different colours so fire controllers could tell which salvo had been fired by which ship. Depth charge throwers ("K-guns") could be used to deceive enemy spotters to believe that the target was straddled when it was not (this was greatly complicated by the use of dyes and dependent on seeing the salvo being fired). It was also possible to group the artillery of one calibre into two or three groups that shoot at different elevations in order to quickly find the correct elevation by observing which impact group was more close to the target (bracket fire). Knowing the correct distance to the target and even the two ships' movement vectors accurately and doing all calculations correctly (including coriolis force correction) would not necessarily suffice to get the elevation right on first try: The temperature of the propellant, barrel temperature, air temperature, air humidity, how much the barrels were worn and wind also had an effect. A radar-only fire control without impact splash observation would have failed at medium and long ranges with the state of the art of even 1945.

Secondary artillery could use the same sophisticated fire control process as primary artillery.

The targeted ship would make evasive manoeuvres when straddled, degrading or resetting both the fire control process against itself and its own fire control process (if it has any and isn't completely blinded).

This combination of fire control and countermeasures rarely if ever happened in perfection. Smokelaying is tricky in windy conditions and some navies had good-enough radars only late in the war (Japan) or never (Italy). The battle in the Java Sea saw Japanese cruisers using the smoke+spotter plane combination, though. Radar-controlled fires were used as well, albeit sometimes with surprisingly bad results (the Bismarck was very poor at getting the elevation right, for example).

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An aircraft carrier as a mere support ship without any torpedo bomber or (dive) bomber could still have had decisive impact on a battlefleet engagements of the 1930's by providing smoke, spotters (replacing the more fair weather-dependent floatplanes and flying boats) and fighters to chase off or down enemy spotter planes. This begs the question why some navies (Germany, Italy and mostly also France) neglected the aircraft carrier so very much. It was already a decisive asset without high performance aircraft (Morse radios/wireless telegraphs were already tested in aircraft during the First World War).

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Yet again, I saw no trace of public pressure on navies to correct such a deficiency during the 1920's and 1930's. The naval discussion in Germany was about the expenditure for the Deutschland class (the later so-called pocket battleships*) until dictatorship took over and public discourse was muted. A similar excuse can be given for Italy, albeit as far as I know their dictatorship would have tolerated pro-carrier enthusiasm  while censoring negative critique. Their navy was barred from having aircraft in favour of their air force, so I suspect their naval top brass simply passed on a critical naval asset because it wouldn't have been fully theirs (the carrier aircraft would not have been navy-operated). I see no excuse whatsoever for France, which had a carrier arm that badly stagnated with the Béarn**.

So why were such severe shortcomings not corrected under public pressure in general? It wasn't just the dysfunctionality of dictatorships. The story of anti-air artillery during the 1920's and 1930's was a farce all around the world. The ridiculously poor quality and also ridiculously poor quantity of anti-air guns in that period was in stark contrast to the known threat of torpedo bombers of the Interwar Years. Their heavy and still very short ranged (low muzzle velocities) medium anti-air artillery was even too weak to protect their own spotter planes from enemy planes even only overhead themselves. Even ships such as heavy cruisers were often only equipped with four weak heavy anti-air guns and a couple machineguns. Moreover, several exercises thoroughly embarrassed navies, as they failed to hit the aerial target for extended times.

It's a general problem with (relatively) highly technicized armed forces in peacetime. Warfare against peer or better opposition may reveal their deficiencies, but most of the time armed services can hide their shortcomings behind the veil of secrecy.

It's a cautionary tale regarding how much top brass can be trusted by the public.

S O
defence_and_freedom@gmx.de

 In kind you want yet more video about naval gunfire control:

*: The Spanish España class deserves this title much, much more.

**: Which also had poor quality aircraft during the 1930's.  

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No good title

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There were a couple ages-long tensions regarding force composition and armament in land forces:

One example was the conflict of choosing between melee and missile capability. There were archers with good melee capability (such as the Babylonian troops with bow and spear), but much of the time missile troops were poor in melee and melee troops were poor or mere targets at range. Attempts to create a hybrid that was good at both were made, but didn't seem to be successful enough to finally settle the question.

State of the art during the mid-17th century was to have a growing share of missile infantry (musketeers) and a waning share of melee infantry (halberdiers) to protect the missile infantry especially against cavalry. There were also some late attempts to combine missile and melee prowess, such as by the double-armed man with longbow and pike (the sword didn't count, being a mere sidearm).

The arrival of practical bayonets seemed to  settle the issue. The musketeer  became able to turn his musket into a lousy spear. It was good-enough to scare horses and the shots were good enough to scare hostile infantry. Some attempts were made to improve the melee prowess with blade sidearms, but they proved largely impractical (and the iron alloy quality for blades was quite expensive).

Then - a long time later - the problem came up again. Again, there were two kinds of infantrymen; submachinegunners with short range firepower and riflemen with long-range firepower. It took only a generation to harmonise this by moving towards intermediate cartridges and the assault rifle.

Now we hear people 'whining' about supposedly insufficient range (that is, from mountain to mountain) of such cartridges, and more powerful single shot rifles ('designated marksman rifle') were introduced, in yet another effort to enjoy more longer range specialists' benefits.

The lesson is probably that we should be glad to have a hybrid, but there will always be people who think they're smarter than the compromise and long for the benefits of specialisation. I guarantee you; the more specialisation we add, the more people will think that the hybrid is the smarter choice.

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Another such tension was about armour; how much protection is the right level of protection?

Heavily armoured warriors / soldiers usually are more capable in melee. Lightly or unarmoured troops are cheaper, quicker, have better endurance, are better-suited for extreme temperatures, can swim and unlike some of the most-armoured troops types they do need no servants.

Rome attempted to standardise its troops into armoured troops under Marius, probably because this was best-suited for professional (16, 20 years of service) troops. This was hugely successful, but they had to support their core of professional troops with lots of specialist and mercenary troops, most of which were much less well-armoured.

The question about armour appeared to have been answered for good by the late 18th century when even heavy cavalry no more used even only breastplates. The bullets of muskets had good penetrative power and armour seemed to be quite pointless. It was reintroduced for a short stint during the Napoleonic Wars (for cuirassiers, but other troops added at least some head protection as well).

Iron manufacturing improved, and 'bullet-proofed' body armour was tried again and again from the mid-19th century to WW2. It never made it into general usage, though steel helmets did in face of the high explosive munitions' fragmentation threat. Other materials were used to add protection tot eh torso against fragmentation, but only by the 1990's did the bulletproofing of torsos take off again. Helmets were bulletproofed against rifle bullets again sometime around 2010.

Again, it's nothing but an ancient struggle. The drawbacks of personal armour protection remain largely the same (weight, cost) while technology swings the pendulum around.

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The force composition between highly mobile (cavalry) forces and rather slow-moving (infantry) forces was another such struggle.

The pendulum swung towards mounted forces during the migration period, and swung back towards dismounted forces in the 14th and 15th centuries (in Europe). The great increase of rifle firepower during the mid-19th century seemed to make cavalry obsolete save for mostly non-combat purposes, but the motorization seemingly pushed the pendulum back towards  highly mobile forces, up to complete motorization. On the other hand, horse cavalry forces were not really much quicker on long-distance marches than infantry anyway. Horse cavalry had its advantage mostly in battle mobility and in quick marches for a day or two as required for reconnaissance. We still have a similar difference between tracked and wheeled forces; tanks are more mobile off-road, but wheeled mobility gives most troops actually better march mobility than the tracked tanks possess. So motorization did not really push the pendulum around all that much; the overall level of mobility was increased (albeit not by much in face of opposition*).

Theorists of the 60's to 80's thought of the helicopter as being the true high speed alternative on the nowadays, but their costs grew to such extremes after the 1960's that their use en masse has become unaffordable.

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Professional high quality troops vs. cheaper low quality troops in greater numbers. Frankly, this choice almost always ended the same way; a mixes force was more cost-efficient to both a high end-only and low end-only forces in land warfare. The only exception I can think of is the enlightenment age when armies became quite homogenous in their internal quality in Europe. There were Jäger and Grenadier units among more common Prussian Füsilier infantry and there were different kinds of cavalry, but overall the German, princes, French and British appeared to have applied high expectations to all their infantry at least and the rather mixed concept and mixed quality Austrian army did not prove superior to this.

The idea of all-high end land forces was revived by de Gaulle in his theoretical work, but an all-mechanised force still seems impractical and most importantly, we know it would be inefficient.

The interest in all-professional forces was renewed post-Vietnam War, but "professional" did not necessarily equate "higher quality" compared to long-serving conscripts as peacetime comparisons between U.S. Army and (West) German Heer revealed. Nowadays we have good reason to believe that even professional forces need a strong reserve personnel pool.

S O

defence_and_freedom@gmx.de

*: I remember a 1990's article from an American military professional journal that showed how the advance speeds of quick campaign moves didn't change much with motorisation. Pre-motorisation armies were often very quick for a couple days as well. Motorised armies didn't come close to exploiting their technical speed.

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Shilka, the revolutionary nightmare

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(I exhausted my supply into the recent link dump, so I had to dust off and tweak an old draft about hardware history to maintain the weekly schedule.)

The most influential move in Cold War air warfare was probably the introduction of the ZSU-23-4 'Shilka', as it changed air warfare from the late 60's to the late 80's in conjunction with the SA-6 "Gainful"/2K12 "Kub" battlefield area air defence missile.

I'll try to substantiate this claim, of course:

Soviet(-style) battlefield air defences were never particularly respected by German or later NATO air power until the introduction of the Shilka. The habit of Red Army troops to shoot at attacking aircraft with everything they got (that is, with all rifles) was meanwhile dangerous enough to largely prohibit ground attack mission profiles which required much air time below 300 metres altitude. The German WW2 battlefield air defences (mostly calibres 20 and 37 mm) were plenty and dangerous, but they didn't prevent punishing air strikes either (German troops used their machineguns, but rather rarely their rifles against aircraft).

ZSU-23-4 Shilka, three ZSU-57 in background

All this changed when there were finally plenty self-propelled anti-air guns (SPAAG) / Flakpanzer in service with a 3D radar and ballistics computer. The Soviets had introduced the Shilka with four 23 mm autocannons, search and fire control radar and fire control computer in the mid-60's and battlefield air defence potential made a huge leap forward. They did not upgrade their older twin 57 mm SPAAGs with at least a rangefinder radar to complement the Shilka with some longer effective range (nor did they produce their expensive twin 37 mm SPAAG design). Instead, the SA-6 was about to deal with anything flying too high for the Shilka, at least in theory (or even more theoretically, the SA-9).

Meanwhile, the new portable Redeye (American) and SA-7 (Soviet) man-portable missiles were easily countered with flares and evasive manoeuvres (including exploiting the sun) and didn't force much of a change in tactics themselves (the same applies to the SA-9).

The common air/ground mission profiles which gave strike aircraft a great bird's view on the battlefield, road or fixed target had become very dangerous, for the aircraft would typically be engaged by ZSU-23-4 or SA-6 at those altitudes.

The best choices for ground attack on a march column had been a combination of unguided rockets and cluster bombs, maybe even use of autocannons (the Hunter's four 30 mm cannons were particularly effective) - applied in a shallow dive. The Shilka still allowed for this, but only from a rather high altitude, with associated loss of accuracy and increase in dispersion. The attack with 'iron bombs' was similarly reduced in efficiency.

This could have been compensated for with an increased usage of guided munitions, of course; laser guided munitions, Walleye-like and Maverick-like munitions. 

The reinforcement of the Shilka with the SA-6 after a few years reduced this possibility to a niche approach.

The Yom Kippur War showed the dilemma: Fly high and the SA-6 may kill you. Fly low and the Shilka may kill you. Fly very low and you're not going to see much, nor have much time between detecting targets and passing them. Otherwise very useful munitions such as unguided rocket pods were of marginal value at very low level and bombs had to be adapted, too.

The Shilkas were more numerous and mobile than the SA-6 radars, so the latter became the target of choice to crack this team. But what was possible on the Sinai peninsula would not necessarily succeed in Central Europe, against the numbers and training of the Warsaw Pact.

The problem was simply that WW3 - if conventional - was expected to last but weeks before all might be lost (similar to the Yom Kippur War), and air power absorbed by taking out battlefield air defences first would not help much.

Up to the late 60's the North German plains were a dream for strike aircraft, as they provide much simpler terrain in which attacking columns could quite easily be found and engaged. Meanwhile, Central and South Germany are rather hilly with many woodland hilltops and strings of buildings adjacent to roads. Many roads are furthermore in woodland and thus visible only from two directions (fore, aft) and straight above.

The arrival of Shilka meant that suddenly the hilly terrain became more favourable, as the hills made radar-based air defence much more difficult. SA-6 threats could be countered by going very low level for a few seconds, and Shilka search radars had an effective early warning range shorter than the line of sight to the surrounding hills; often too little for the full engagement sequence.

This then more favourable terrain was still the less favourable terrain of the early 60's, though: Air power had greatly lost in efficiency due to the Shilka (ceteris paribus).

The respect for the area air defence missile threat such as the SA-6 was high enough for NATO to not follow the guided munitions path fully, but only partially. The new Jaguar and Tornado strike aircraft designed for the 1980's European theatre of operations made use of almost no guided ground attack munitions, for example.

Instead, very low level flight including the use of terrain following radar became the big fashion, despite the fact that look down/shoot down Doppler pulse radars and matching missiles had been introduced during the 1970's already. The dominant ground attack profile proved to be awfully susceptible to modern fighters, and even worse: Any fighter escorts were pressed into roughly the same profile and thus inherently disadvantaged against modern defending fighters.

Some attack capabilities from convenient altitudes were maintained, though: The Yom Kippur War had also showed that the semi-stationary SA-6 batteries could not support ground forces with their protective umbrella during fast-moving campaigns. Armoured spearheads exploiting a 'breakthrough' would typically still be vulnerable, and there were never enough missile batteries on either side to protect the rear areas well (airfields, bridges, depots). NATO, for example, maintained a kind of SAM belt from the Austrian/Swiss border to the North Sea, with many rear locations protected only by fighters or low level defences.

NATO did ultimately bet on the ability to take out or suppress the vital radars of area air defence batteries with its anti-radar missiles: An approach initially invented during WW2 and introduced for good during the Vietnam War.

This didn't help much against modern SPAAGs, though; laser rangefinders soon potentially gave SPAAGs the ability to defend against low level attackers without any use of a radar. The second generation of portable very short range air defence missiles (famous Stinger and others, amongst them the very countermeasures-defying laser beam rider missiles) added to this.

 

As a result, NATO air attack doctrine went back to the 15,000+ ft (more than 4,500 m) attack altitude and began to make use of many guided munitions. The technological advance and large production runs allowed for some very cost-efficient guided munitions, especially cheapened laser guidance or satellite navigation guidance kits. Sensors (imaging infrared optics and modern imaging radar) allow modern strike aircraft to attack just as well form this altitude as earlier strike fighters were able to do from much lower ones with 'Mk1 Eyeball' sensors.

Post-2000, the Stinger-type missile threat appears to be largely defeated by sophisticated technical and tactical countermeasures, but the laser beam riders and the autocannon threat (with laser rangefinder, computer and automatic target tracking sensor) keep the low altitudes dangerous when present.

Without Shilka and to a lesser extent its successor and relatively few Western counterparts all this wouldn't have happened.

1970's strike fighters could have flown at a convenient altitude for spotting targets, diving and temporarily flying very low when a missile battery threat was detected. The modern strikefighter of the 1980's might have utilized an underbelly autocannon pod to easily take out anything but main battle tanks from a convenient altitude (maybe 2,000 metres) while circling the target area. Unguided rockets, Maverick-like anti-tank missiles and wind-correcting cluster bombs with timed release might have reigned and we would never have seen submunition pods such as JP233 or MW-1. The typical strike fighter might also have had a much larger wing area like the F-16XL, because there would have been few terrain following mission profiles in low altitude dense air (which create problems for low wing loading aircraft and thus led to relatively small wings). Area air defence batteries could have been engaged by triangulating their position and attacking them low and close, since they wouldn't have been protected against this kind of attack by SPAAGs.

 

Air and sea warfare are so very much dominated by technology despite the importance of skill, numbers, support and weather that a single technological progress is able to change the entire picture. In the case of Shilka, this progress was actually announced two decades earlier, when the combination of SPAAG with fire control radar and fire control computer (a search radar was still unnecessary due to lower aircraft speed) was first feasible and envisaged. The nuke-crazy 50's may have delayed the inevitable revolution by a few years.

The result was that the face of modern air attack  was changed, as it had to adapt to the threat.*

S O

defence_and_freedom@gmx.de

*: Strangely, the loss in efficiency was not followed by a shift in budget priorities; NATO had already given up the idea of countering Warsaw Pact tank quantity in a symmetric arms race despite the German experiences from WW2 which indicated that this was feasible with enough good arms. The result was that Western great power militaries have become dependent on aerospace superiority.

 

P.S.: I link a lot to Wikipedia, but don't mistake this as a link to sources. The links are meant for those readers who cannot remember the specific thing at the moment. I cover a wide range of topics and do not expect the majority of my readers to have a matching range of interests and knowledge, so I make the texts easier by adding these links.

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Exotic ancient weapons: (IX) Penobscot double bow

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First, an engineering view of the double bow.

The Penobscot bow / Wabanaki bow / Mi'kmaq (double) bow is an advanced version of a cable-backed bow with very different mechanics. It's different in its performance from bows that simply use wider or thicker limbs or more limbs.

photo uploaded by "Judson"/"Judson127", taken from here

Mechanical engineers learn that everything can be considered to be a spring; even a solid block of steel is a spring. We can apply a force to it and it will either compress or elongate. We usually cannot see the tiny change in its dimensions, but it happens. Its spring constant simply requires a powerful force for very little change of its dimensions. Spring steels in coil spring shape make it much easier to experience how steel yields to mechanical forces.

A bow can be considered a spring as well - you pull harder, it yields more - and just like a spring, it stores energy in the process. This energy can be released for the purpose of accelerating the arrow (or with an arrow guide, the dart).

Bows (and many other spring arrangements) have no spring constant, though; the amount of force required to pull the arrow back by one more centimetre depends on how far you already pulled it back. The bow design doesn't simply compress or elongate, but changes its shape as it yields to the pulling force (the string notches approach each other).

The ideal bow design would accelerate the arrow with about the same force regardless of how far it's still drawn (but that's not feasible). The force must not be excessive (or the user couldn't draw and hold the drawn bow well or at all) and should not be low (for the sake of accelerating the arrow well).

This cannot be done with a single spring; you need a set of springs (or a more complicated design such as the recurve or composite bows) to approximate this ideal.

Springs of different spring characteristics can be arranged to  create a non-linear spring curve; this way compressing or elongating by a certain distance doesn't require the addition of the same force regardless of how much the spring system has already been manipulated.

The double bow is such a two-spring-ish system in spirit. The small front bow is not just an overly elaborate way of making the bow stiffer; it actually modifies the spring curve (requires more force to draw at first, thus also accelerates the arrow more) as a parallel spring, and by consensus of double bow users, it does so in an advantageous way compared to a self bow of equivalent technology. You get more performance out of such a bow for the same maximum (28" draw) draw 'weight' than with an otherwise equivalent technology self bow.

That, by the way, is the reason why people who create double bows with the front bow almost as long as the main bow either didn't get what the design is meant to accomplish or are merely trying to create a bow that can make do with poor material (poorly suitable woods). A proper performance double bow has a short front bow that gets fully drawn fairly soon in the drawing motion.

(BTW, the Penobscot double bow is supposedly not really "ancient", supposedly it's just over a hundred years old - I doubt this, but don't have sources that mention it earlier.)
  
edit: I decided to add this link, asthe author there actually shows a diagram with force-draw curves. The Penebscot double bow design essentially leads to a quicker rise in draw strength on the first centimetres (inches) of draw. During the shot, the arrow gets accelerated with more force when it's forward that much again. / I also cleaned up the text above a bit.

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Second, this video on African martial arts (unrelated to double bows):

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Third, some general remarks on non-firearm weapons:

It's amazing how after some study one becomes mostly able to tell the way a weapon was meant to be used by merely looking at it, including some requirements for the associated armour.

The hilt of a blade weapon in itself can be formed to almost force the user to use a certain motion for slashing. This particular hilt design alone tells the observer that the blade will be very curved sabre's blade.

Curved blades typically require a relatively high quality material because they almost never have two edges, and one edge could quickly become dull in an extended battle. Curved blades are especially meant for cutting, so holding a good blade is important (harder edge allows for a sharper edge) and difficult (harder edge ~ more brittle edge).
The one exception I'm aware of are the bronze age sickle swords, and their users were probably prepared to sharpen their weapon with a grindstone on their own as in agricultural use of sickles.

Curved blades are never made for thrusting into the body; they are made for cuts and slashing motions. The cutting motions may include a pushing and pulling motion, but only to cut along the side of the target. The pushing cut isn't really an option with forward-curved blades such as sickles, romphaia or falx.

Straight blades can be built for thrusting into organs, but don't necessarily have the point for it (Celtic swords were largely limited to slashing, as the point was often dull). Very fine points give away the intent to penetrate an armour type that's not very good against thrusting attacks (typically mail), and are thus uncommon in areas where such armours that are vulnerable to thrusting attacks are rare (example East and South Asia).

An extreme case are the smallswords and the like - straight sword-like blade weapons meant exclusively for thrusting with the point, without a shard edge. These continued to be in use after mail armour fell out of fashion in almost all of Europe (Balkans excluded). Frankly, my suspicion is that they were optimised for light weight, as respectable sidearms that aren't too much of a burden on their user.

Large handguards tend to be associated with no use of shields, or use of shields very unwieldy (pavise) or very small (buckler). Handguards can then help protect the hand when you cannot do it with a shield. An exception is the customary retention of large handguards along with late medieval plate armour, but one should keep in mind that swords were sidearms and thus also (if not primarily) used when the wearer wasn't fully geared up.

Blunt weapons such as maces and hammers (also hammer components in weapons such as the pollaxe) were either an extreme budget solution (clubs) or a response to very effective armour. Blunt force can even be effective against plate armour and equivalent helmets when blades and pointy weapons fail. The latter are usually built to be nimble in their use and thus quite lightweight. Axes and blunt weapons require a lot of mass where it matters the most; at the end of a pole or short shaft.

Single-handed weapons that are quite long among their kind (mace, sword, sabre) tend to be cavalry arms. Their increased length compensates for poor riding skills* or a loss of dexterity caused by the user's armour.

Lances and pikes were usually held low, while spears were held high (if used single-handedly) for a greater choice of movements.
Polearms with oval pole cross section and/or dedicated axe head, spike or blade elements (examples pollaxes, halberds, naginatas) were meant for slashing and/or swiping movements. This in turn indicates that they were meant for two-handed use, and thus lead to an emphasis on good armour protection for the user, since shields would be quite impractical.**

Javelins are particularly interesting; the very light ones were used in great quantity by dedicated skirmishers and cavalry, while the more elaborate ones such as the famous Roman pilum (no doubt the most advanced and most capable javelin design ever despite lacking an amentum or spear thrower) were carried in small quantity (one or two per legionary; that's still up for debate). The pilum's purpose was threefold; a demoralising/shocking salvo, disabling shields by sticking to them (making them unwieldy and enabling the enemy to push the shield sideways) and finally an emergency use as a spear, particularly against cavalry.***

Spears are capable weapons for one-on-one situations unless the enemy has good armour. Their use was typically rooted in at least one of three motives; poverty (spears as versatile budget option), horsemen threat (spears as anti-horseman weapon,**** obviously not helpful against missile horsemen) and third, disciplined forces employing closed order tactics (example Greek phalanx).

As with swords, the width of the spear tip usually indicates whether a spear was meant for use against armoured opponents or not. A wide, leaf-shaped spear tip would be for use against unarmoured opposition (example iklwa), or for the hunt. Boar spears and some other spears had some guards to limit penetration.

Particularly short stabbing blade weapons such as the Spartan short xiphos versions or Germanic seax were associated with very restricted close quarters combat, such as fighting in a phalanx or shield wall where the gaps between shields and the air above could be used for very short stabbing motions. Another use for such short sidearms was on board of warships (for boarding actions), usually with a blade that's well-suited to slashing (which makes it useful for cutting tows).

Likewise, the design of shields allows conclusions about their use.

S O

defence_and_freedom@gmx.de

*: Not all horsemen were good at horsemanship games and thus capable of picking stuff up from the ground while riding, so they needed longer weapons to strike targets lying on the ground. That in turn is important because to simply lie on the ground is a reasonable approach to protect oneself from a cavalry charge; horses will avoid to step on such irregularities to avoid injury.

**: This requirement finds in exception of the very late halberd-ish weapons such as partisans of the firearms era, about 17th and first half of 18th centuries. The same applies to bayonets. The requirement may not be met because of economical reasons, but two-handed polearms were rare when good body armour was unaffordable unless the use of powerful halberd-like weapons made it quite pointless anyway (example Japanese warrior monks with Naginatas).

***: The pilum slowly fell out of use when the longer spatha sword gradually replaced the gladius sword. The disciplined Roman infantry (even auxiliary infantry) was able to resist shock cavalry with disciplined closed order formations (horses don't run into spear tips, but the don't run into shield walls either) and a longer sword made the need for some spear-ish weapon against cavalry less pressing. There may thus have been such a relation between the rise of the spatha and the decline of the pilum (in favour of plumbata and cheaper simple javelins). Alternatively, the increased use of light javelins by horsemen may have led to a better opinion about them, eroding the pilum's role. Last but not least, the late imperial Western Roman infantry faced much more cavalry and actual spears became much more common in service again. Spears and pila don't go well along because spearmen tend to keep close formation, whereas pila require some more space for the user to throw. In the end, the pilum+gladius combination was unique to late Republican and early Imperial Rome, and a hugely successful approach that seemed to have been suboptimal in other times and places.

****: Long straight swords could be used to deter cavalry as well (Pallasch weapons were used by cuirassiers of the 18th century almost as if they were spears).

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Early breechloaders and production technology

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The line infantry combat of the late 18th century had - aside from skirmishers - two lines of three (British: two) ranks depth opposing each other and unleashing salvoes at each other with smoothbore muskets. The disciplined salvoes would degrade into uncoordinated single individual shots quickly as losses and fear break the discipline. The rate of fire of the best-drilled troops was 3 rounds per minute, but 2 rpm was more usual.

The muskets were not accurate at all, and even lacked real sights because sights were largely superfluous anyway. Even a large target such as a line formation of men would be hit by a few per cent of the men at 300 m distance, with salvoes fired much earlier than at 200 m distance being rare due to their inaccuracy.

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Now imagine a breechloading (quick-loading) rifle such as the Ferguson rifle was introduced en masse.

The rate of fire would have been increased by a factor of two at the minimum. 

The lethality of aim would be multiplied by a factor of more than two at more than 100 m, and still be substantially better at less than 100 m.

As a consequence, the first salvo might have been unleashed at 400 m already, and at a stead 4 kph pace this would expose the advancing hostile line to three minutes of lethal and demoralising fire before they would commence firing at 200 m distance.

The riflemen would also have been able to reload and shoot while lying, allowing for a two rank deep formation of lying and kneeling riflemen. This would have reduced the target silhouette by about a third compared to the standing three rank line. A third rank would not be advisable because the blackpowder smoke would have blinded the riflemen if they stood in a too dense formation.

Such breechloading rifles would have yielded at least two firepower multipliers greater than four and a survivability multiplier and in addition to this the skirmishing would have been vastly superior and Lanchester's equations point out that the effect on the casualties taken would be even greater than the basic firepower and survivability multipliers.

So why wasn't such a rifle introduced en masse earlier?

No doubt the basic idea of a screw breech was known long before the Ferguson rifle!
(Actually, one such rifle dates back to 1667.)

For an answer, let's look at an even greater and even older marvel of firearms history:

That's merely anecdotal evidence, but it's nevertheless extremely likely that the (in)efficiency of production (thread cutting for the Ferguson rifle, intricate parts in the Lorenzoni pistol) was the culprit. That's also why matchlock firearms were much more affordable than wheellock firearms. The unreliable yet also cheap flintlocks firearms later replaced both, after a series of short-lived interim solutions.

Let's assume an ahistorical scenario: A 17th or 18th century prince had a genius of the kind of Leonardo da Vinci on hand and commissioned him to devise a manufactory for the cost-efficient quantity production of screws, rifled barrels and flintlocks. A decade later, an army depot would be filled with 25,000 screw breechloading rifles and copper engraving plates for rapid education on a new set of drills and tactics.

In preparation to a war the entire army would be retrained during a summer, producing a field army of 30,000* with vastly superior firepower ready for the beginning of the next campaign season in spring.

The result would have been an unbeatable army, and the dominance of its infantry firepower might have eliminated battlefield (shock) cavalry much sooner than historically and generations would have been deceived into thinking of artillery as rather unimportant in battles.

Real quantity production even with exchangeable (instead of laboriously fitted) parts became important only during the mid-19th century. The huge importance of this development is largely hidden to those interested in firearms history because the percussion caps, the Minié ball, the Dreyse needle rifle and metallic cartridge cases revolutionised firearms at about the same time.

A cheap thread cutting manufactory process devised and implemented in the early 18th century could drastically have changed Europe's or India's history.

a few links about the Ferguson rifle:
www.historicalfirearms.info/post/89997396784/ferguson-rifle-major-patrick-fergusons-ordnance
americansocietyofarmscollectors.org/wp-content/uploads/2013/05/B024_neal.pdf
www.guns.com/2011/08/12/qthe-gun-that-could-have-won-americaq-the-notorious-ferguson-rifle/

S O

defence_and_freedom@gmx.de

*: Larger armies were unhandy, since they would take too long marching on a single road from one bivouac to another. That's why later on Napoleonic corps were roughly of this size and armies of 20,000 to 30,000 men were more common than all larger ones in military history. 

P.S.: Breechloading also offered advantages regarding cleaning the barrel of all the foul from burnt blackpowder. You can pull some cloth on a cord or small chain through the barrel to clean it, as with modern rifles. The Ferguson rifle wasn't quite optimised for this yet (nor had proper iron sights). 

Edit April 2016: I should have mentioned that the flintlock technology didn't really allow to exploit the full rate of fire of such small arms becuase the flintstones became unreliable quickly, after a few shots. A return to the pyrite-based and much more expensive hwelllock might have been advisable for these two firearms, but that would have increased the price even further.

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Shock vs. fires - the ancient choice

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There's an ancient debate about shock attack vs. fire attack. Many descriptions of 15th, 16th, 17th, 18th, 19th and yes, also 20th century generals* include remarks about how the person preferred shock over fires. The choice of words varies, of course. A typical way to describe it is to mention a preference for cold steel (bayonet assault).

The choice (and in part trade-off) appears to be very, very old. Still, the seeming historical continuity of the debate can deceive. Here's an earlier Defence and Freedom text describing a similar problem:
 

2010-02 Sun Tzu and cities

The choice is between closing with the enemy and staying at a distance (preferring stand-off fires).

To go close to short range (melee) combat tends to promise decisive results because troops cannot survive close to hostiles for long and usually need to fight it out quickly.

To stay at a distance is subjectively less risky, and tends to deliver results more slowly. It's also more expensive materially (ammunition mostly - blackpowder and especially its salpetre was very expensive and scarce).

The choice may be ancient, but the conclusions depend on the state of the forces (and their technology).

Russian troops weren't exactly the most sophisticated during the 18th century, butwell capable of shock attacks. Suvorov won dozens of battles by exploiting this and is one of the historical generals known for a preference for 'cold steel'. Other armies preferred to impress with firepower, such as the Prussians.

The balance between shock and fires was a tricky one during the 17th and 18th centuries, and a mere look at the weapons cannot explain the issue. I'll give it a try with what I (believe to) know:

Battle of Poltava, 1709, painted 1726

The musket was a firearm of very, very disappointing performance in almost every regard. This didn't even matter much given the poor training and the smoke of the blackpowder, though. The musket began to be useful at about 200 m, and getting the first salvo off was important. You wouldn't want to fire the first salvo at a too long distance due to the poor accuracy, though. Then again many soldiers didn't (and don't) really want to hit anyone anyway.

The second salvo was already very inaccurate and hasty even if it was fired at shorter ranges simply because the smoke usually obscured the enemy. Then again, you couldn't really aim much with the almost straight buttstocks (those looked better on the parade-ground) and no real sights anyway.

The physical effect of musket fires was thus quite unsatisfactory and gave rise to an interest in melee combat which we don't have any more because of much better firearms.

The psychological effect of firearms and their effects was considerable, though - especially if one line just felt that the other line was firing salvoes at a faster rate.

The bayonet matured to a form which allowed
loading and firing with bayonet fixed.

The argument for shock attacks didn't rest on an excellent weapon either. The bayonet was -even when matured as a technology- a very poor melee weapon. A dung fork was a better melee weapon than a musket with a bayonet. 1,000 BC spears were better melee weapons than a musket with a bayonet. Almost everything but a knife was better for melee combat than a musket with bayonet fixed. Maybe even a knife.

The raison d'être for the bayonet was really to deter and if necessary stab horsemen (or horses) - it wasn't much worse than pikes in this job.

Swords and sabres were added to musketeers/fusiliers during peacetime on several occasions because they seemed to be a good idea. They were ditched during wartime on several occasions.

 

Why?

 There was almost no melee combat during age of musket battles apparently!

Yet, few soldiers [meant: infantrymen] actually fought each other with cold steel. At Austerlitz, the Russian Guards made a classic 300-yard charge, but were exhausted after breaking through the first French line and driven back by fire. Generally, it was the threat of the bayonet, and not the actual clash that decided an issue. After studying the casualties suffered by units in a number of hand to hand combats, Surgeon General Larrey of the Grand Army found only five bayonet wounds and concluded that the effect of the weapon was primarily psychological. And one of Wellington's senior medical officers, George J. Guthrie, asserted that formed regiments 'charging with the bayonet never meet and struggle hand to hand and foot on foot; and this for the best possible reason, that one side turns and runs away as soon as the other comes close enough to do mischief.'

 "The Art of Warfare in the Age of Napoleon",

G.E.Rothenberg, 1979, p.69

There's also a nice quote from the other end of the blackpowder era, from when Tercios with a combination of pikemen and arquebusiers dominated West European battlefields. The author back then in the late 16th or early 17th century stated that one shouldn't kill pikemen if avoidable, for they hardly ever kill anyone themselves who didn't charge against them on horseback. The pike was later replaced by the bayonet and the expert swordsmen known from early Tercios had already disappeared from late Tercios. Regrettably, I didn't rediscover the exact quote.

a typical formation from the early age of muskets

 

Even battles with plenty successful "shock attacks" had little infantry-on-infantry melee combat. This is one of the least intuitive and most unbelievable observations of 17th and 18th century authors about battles in the age of muskets.

One closed order infantry formation was sent to attack another, they shot at each other, the attackers keeps advancing after salvoes again and again - and then one line formation broke. The men simply fled. This may have been the attacker or the defender, but actual melee combat with men stabbing each other with bayonets or using sabres was very uncommon during battles.** Sometimes the defenders did a counter-charge to break the already cracked morale of the decimated (by fire) attacking formation, but the result was still that one party would break and flee, and there would usually be no melee combat on grand scale.

This observation explains why the very poor bayonet was sufficient as the only melee weapon, and how quickly closing with the enemy while under fire wasn't only the more decisive tactic, but at times even the less bloody one. It sure saved blackpowder and lead and allowed less sophisticated forces to prevail. Superior discipline was the best approach to avoid being the one whose formation breaks and disintegrates. It helped to soften up the enemy more with quicker salvoes and made the men more steady in face of impressive salvoes and seemingly irresistibly approaching forces.

This explains why the line infantry forces of the 17th and especially the 18th century were drilled incessantly and why discipline had become the focus for almost all infantry units in Europe.

It all kind of makes sense, but only in the context of the period's technology (particularly the drawbacks of blackpowder) and if one pays much attention to morale and discipline.

And this is why the old times' debates about shock attack vs. fires attack is utterly irrelevant today. It's seemingly a timeless, persisting debate about a seeming constant in warfare - but the answers need be found anew again and again as the nature and technology of warfare change.

Bonus part:

Only to show how tricky the military trade is at times: It still made sense to train the infantry in bayonet combat, and then preferably to pitch them against recruits in mock combat in order to instil great confidence in them. Confidence in the own bayonet combat skills made it less likely that the own formation would break first.

Even more tricky: Non-commissioned officers carried long polearms (spontoons) which are usually called obsolete even at their time by book authors. Those were pointless anachronisms, right?

Again, no - it's tricky. Those long poles were used to push and keep the line infantrymen into formation. They were held horizontally and crosswise for this. A fusilier who wavered and made a step back would be pushed back into line again with the spontoon. Spontoons were rather decorated tools than weapons.

Again; it's about morale and discipline, not about the (low) inherent quality of the 'weapon' itself.***

S O

defence_and_freedom@gmx.de

*: There wasn't much of a choice prior to the arrival of firearms because arrows were quite easily stopped with shields or most armours.

**: This appears to have been true since the early 17th century, when early firearms had become more important than pikes.
***: You may find similar thoughts in my 2009 text on flamethrowers.  The morale and discipline aspect of warfare is easily lost to later generations.

P.S.: About modern bayonets: I suppose knife bayonets make sense, for you end up having a rifle and a knife anyway, and there's almost no compromise necessary to enable knife bayonet usage. The only real benefit is in handling prisoners of war or in deterring civilians, though.

edit: The Weapons and Warfare blog has more:

REBEL FIRE DISCIPLINE AND THE BAYONET ATTACK I

REBEL FIRE DISCIPLINE AND THE BAYONET ATTACK II

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Infantry firearms calibres - a long history

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(This post was motivated by a somewhat heated exchange with someone who insisted to see a trend.)

Why did we end up with a calibre of 5.56 mm (and others with 5.45 or 5.82 mm)? The understanding of modern infantry firearms calibres requires in part an understanding of their history.

The typical European 18th century service long firearm was a musket. The calibres were astonishingly large, and the typical bullet was actually a spherical ball. Cartridges were introduced, typically paper with ball and blackpowder, and de-mixing of the blackpowder over time was an issue.

 

The famous British Brown Bess may serve as a representative of this era:

It was a smoothbore muzzleloader. The barrel bore was .75" (19 mm) and the typical ball fired was .69" (17.5 mm). The difference between bore and ball (windage) differed between countries, less made loading slower, but the shot dispersion was made smaller. The tolerances in producing these guns were such that substantial differences even in calibre were common (and were tolerable at the time). The heavy ball (about 550 grains / 35.5 g) was fired with a low muzzle velocity of about 1,000 fps (305 m/s); subsonic.

Brown Bess / Short Land Pattern Musket, 18th century (c) Antique Military Rifles

The invention of the Minié ball made the conversion from smoothbore musket to a much more accurate rifle possible without the slow reloading of earlier rifles: The bullet (cartridge) of the Minié ball was subcalibre during loading and thus easily loaded as was a subcalibre ball cartridge, but the gas pressure widened the soft lead bullet and pressed it into the grooves. This enabled spin stabilization of the bullet for a small dispersion and real sights and aiming at individual enemies became purposeful for line infantry. It makes little sense to spin stabilize a ball, though; the typical bullets for rifles are longer than the calibre. The Minié ball actually required this for its function.

The weight of such a bullet became almost prohibitive with the established calibres. It wasn't necessary to maintain the established calibres anyway, for the greater length of the bullet added to its penetration capability. The invention of pressed blackpowder grains made blackpowder more consistent and more potent and helped the rifles further.

The consequence was a reduction of the calibre.

A representative for the typical Minié ball rifle shall be the Springfield Model 1861:

Springfield Model 1861 rifle-musket

It was a rifled muzzleloader. The barrel bore was .58" (15 mm) and such was the bullet calibre after leaving the muzzle. The muzzle velocity of the approx. 510 grain (33 g) bullet was apparently about 960 fps (290 m/s) - both a bit less than the Brown Bess'.

The Springfield Model 1861 rifle-musket was already obsolete before its predecessor was introduced, of course. The Prussian Dreyse needle gun (in service 1848) had finally -after centuries of experimentation - delivered the first truly successful breechloading service rifle. Its only advance was its (initially) higher rate of fire, other specs weren't very different from the rifle-musket competition.

The superior French Chassepot rifle (in service 1867) shall instead represent the late age of blackpowder breechloading rifle:

Chassepot rifle, (c) PHGCOM

The calibre was already no more musket-like, but down to 11 mm. The bullet was down to 386 grains (25 g), but its muzzle velocity was up to about 1,350 fps (about 410 m/s) - supersonic. The bullet wasn't weaker than the others mentioned, but it was lighter. This was a purposeful adaption to the new quick fire capability. In theory (if the rifle works flawlessly), a riflemen could have consumed the previously normal maximum 60 rounds within four minutes of quick fire. The only sensible way to supply the rifleman with the ammunition to exploit the quick fire of his rifle was to use a lighter bullet. This saved both weight and money.

The long-ish shape was determined by the nature of the rifle, so a smaller calibre was the way to go. A lower density material would have been no good choice, as the very dense soft lead was very good for the grip in the grooves (internal ballistics), external ballistics (high sectional density) and for terminal ballistics (flattens in soft targets).

Then came the 1880's and quite scientific chemistry. The first practical 'smokeless' (actually less smoke) powders (actually grains) were introduced (more here). One of their consequences was that quick and automatic rapid fire became more practical because the smoke didn't impede aiming any more. Another was that higher muzzle velocities became achievable.

The former meant that repeating rifles became more important as service rifles in place of single loading rifles: Built-in magazines loaded with a clip became common for decades to come. This meant even higher practical rates of fire and the weight issue became even more pressing. What's more important was the gain in external ballistic performance; the muzzle velocities were approximately doubled.

The German (Mauser) Gewehr 98 may serve as a representative for this era:

Gewehr 98

It was the culmination of a series of troubled designs. Experiments with 5 mm (1892) and 6 mm bullets (1998 at the latest) were unsatisfactory, and bullets were not yet really understood from an engineering point of view. The 8x57 mm "Patrone 88" cartridge with its 14.7 g bullet yielded a muzzle velocity of 640 m/s. This bullet was disappointing. The high muzzle velocity and conventional bullet shape led to compression effects which damaged the barrel and caused too much wear of the grooves.

Research led to the adoption of a Spitzgeschoß* (spitzer bullet) of 9.8 g for a muzzle velocity of 895 m/s. The reduction in weight was intentional, but also a consequence of the new shape. The shape solved the internal ballistic issues and also offered much superior external ballistics. The new bullet design also led to a very different behaviour after impact (terminal ballistics).

This spitzer bullet revolution of the 1900's (developed about 1898, introduced in armies during the 1900's)  followed the initial 'smokeless powder' revolution of the 1890's which in turn followed the conversion to breechloading in most European armies during the 1860's and 1870's. It sure was an era of unprecedented 'progress'.

So again, a drop in bullet weight was accompanied by a jump in muzzle velocity, and this was again due to the technological progress in bullet design, again with minimal alterations to the weapon itself.

It is interesting to see that smaller calibres (8 mm was considered 'small calibre' by 1900) were already tested, but found wanting. Their higher muzzle velocities (of 1890's 5 and 6 mm bullets) were too troublesome until spitzer bullets were developed. Some 6.5 mm calibres such as 6.5x55 mm were used by small powers and Japan, though.

Several rifle calibres of about 1900 were successful and became well-established, not the least because of the huge stocks produced during the First World War: 7,92x57 mm, .303, 7.62x54mmR, .30-06.

These cartridges proved to be too powerful for a practical self-loading rifle at acceptable weight until a solution was found with the Garand rifle. Many prototypes blew up. A semi-automatic (self-loading) rifle didn't seem to be the solution of choice after the experiences with trench fighting and machinegun fire during the first World War anyway; a combination of a rifle with the full automatic short range firepower of the newly invented submachineguns was desired. This was of course even more troublesome than a self-loading rifle.

The way to go was to use an intermediate cartridge, and a solution was found during the 1930's within the usual calibre range (7.75 or 7.92 mm), but with a much shorter, lighter bullet and accordingly less propellant in a shorter case (a Swedish 7 mm light machinegun cartridge didn't succeed). A loss in long range firepower was considered acceptable given the experiences of the First World War. This time, the need to reduce the power of the cartridge drove the specs.

The German Sturmgewehr 44 family of machine carbines  / 'assault rifles' shall serve as a representative, albeit the more notorious AK-47/AKM fit in the same era:

Sturmgewehr 44

It kept the calibre of 7.92 mm calibre to facilitate quantity production with available tools and machines. The bullet weighed 8.1 g and left the muzzle at 685 m/s (late wartime cartridge specs). This was considerably less than the contemporary "sS" 'heavy' spitzer bullet in calibre 7,92x57 mm, which had replaced the original spitzer bullets for in the mid-30's and weighed 12.8 g.**

Last but not least; how did we end up in the 5.45 to 5.82 mm range?

As mentioned, the first assault rifle generation still used the established barrel bores; 7.92 or 7.62 mm, with muzzle velocities around 700 m/s; well below what can be had without excessive groove wear (= a bit more than 900 m/s). There was clearly some potential for improvement for the probability of hit against moving targets (deflection shooting) and against low silhouette targets at unknown distances (flat trajectory desirable).

Another issue was how all-automatic weapon infantry used the bullets; it chewed through truckloads of them. Suppressive fire had become feasible and was found to be tactically very, very useful and also rather relieving for the stressed infantryman. 99.99something per cent of the bullets do not hit anybody, but they frighten many. 

This practice places a greater emphasis on the ability to carry many cartridges into battle, and rather less on the what a hit actually does.

The result was that the developers went back to the 5...6 mm range of bullets, which had been discarded in the prototype stage two generations earlier. The very small bullets weigh very little:

5.45x39 mm (Warsaw Pact): typical bullet about 3.5 g

5.56x45 mm (NATO): typical bullet about 4.1 g

5.82x42 mm (China): typical bullet about 4.2 g

The original introduction of the original 5.56x45 mm M16s as service rifles was probably by chance, but the subsequent adoption of this small calibre range for assault rifles and light machineguns all over the world was not. The move from the original full calibre assault rifle generation to this small calibre generation was driven by the need to carry more bullets into battle at an acceptable weight and bulk. This in turn was driven by the gain in rapid firepower that came from the acceptance of less effective range.

Ironically, the readiness to accept the latter compromise was worn out over time and much of this generation of soldiers wants more range again, asking for a different compromise (or an unobtanium bullet design).

- - - - -

I initially made clear that I'm opposed to the view that the reduction of service rifle calibres is some very, very old trend. I consider it rather as a series of technological (and ultimately also tactical) steps forward which by chance happened to all go into the same direction; smaller bullets.

It's a poor idea to consider this as a trend, though. A belief in a trend may create an impression that this trend may go on, and that may be misleading. It's better to drop the simplistic concept of a trend here and go right after what really mattered; the technological steps and observations of their tactical consequences.

An example why this difference may matter: The next observation that matters may easily be that  we finally look at modern battlefield gunfighting from the perspective known to so many ragtag militias and low budget mercenaries: We may find the performance of our bullets in face of hard body armour as too unreliable, at least without rather exotic subcalibre bullet designs. The consequence could be a short-term ammunition solution (more subcalibre high penetration cartridges; "SLAP") followed by a return to a bigger calibre with bigger bullets which have an easier time penetrating hard body armour. Maybe we even end up with two calibres carried; one for suppression and one for penetration.

A belief in an ancient trend isn't going to help us understand or even anticipate developments, for sure. The current calibre range had already been fiddled with 120 years ago anyway.

S O

defence_and_freedom@gmx.de

*: The French introduced a different kind of spitzer bullet slightly earlier, but it wasn't the kind that became the dominant design: It was a bronze alloy bullet.

**: This bullet design improved the external ballistics (relevant only at long range), but primarily it lessened muzzle flash, muzzle bang and recoil issues of the original S-Patrone. There was also a late-WW2 7.92x57 mm duplex cartridge which had two bullets from the 7.92x33 mm calibre, potentially doubling the rate of fire of the already notoriously high-rpm MG42.

For German readers: Einige Infos entnommen aus "Die deutschen Militärgewehre  und Maschinenpistolen 1871-1945", H.D.Görz, 1994. Auch nützlich: "Waffen der Kabinettskriege", "Waffen der Revolutionskriege" und "Waffen der Einigungskriege" von Georg Ortenburg, 1986-1990

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