Back in 1896 the German army introduced the 77 mm light field cannon 96; it was a normal cannon design with a recoiling carriage. The latter feature is and was widely criticized for being obsolete: The famous French 'soixante-quinze' revolutionised field artillery with the first recoiling barrel carriage which did not require to reset and aim the carriage after every shot (this made a shield practical, too). The 77 mm Fk 96 was consequently rebuilt with a recoiling barrel design carriage and renamed with suffix "n.A." (AFAIK = neue Art; new model).
|7,7 cm Fk 96 n.A. in the field, 1918, (Bundesarchiv Bild 146-1974-054-18)|
The common literature on the new version supposes that it was now a useful field piece, albeit less useful than about as heavy and about as expensive 105 mm field howitzers.
I am quite sure that this falls well short of being an accurate appraisal.
This gun was in use prior to the First World War and during it and a successor design was introduced in 1916.
The list of shortcomings was huge, let's begin with the major difference with its successor type: The maximum gun elevation. 77 mm Fk 96 n.A. had -13/+15° gun elevation, 77 mm Fk 16 had -10/+40° gun elevation. The maximum range can be achieved at about 43° (would be 45° if there was no drag). The old design simply threw away a sizeable chunk of its potential range. Why? Well, the importance of indirect fires was not fully understood before WW1. It was known that the shell is more effective if it descends near-vertically, it was known that you cannot really do much with 15° elevation if you're in an area with woods or on rolling terrain and it was known that indirect fires were valuable not the least thanks to superior survivability (otherwise there would have been no field howitzers). Still, the maximum elevation of the cannon was only suitable for flat lands, preferably with hard and even soil (for bouncing shots with delay fuse).
Next issue; the gun traverse. The carriage was such a primitive box trail carriage that the traverse was only 8°. 8°! This basically means you need to turn the entire carriage after every shot unless your target is stationary. This, BTW, was supposed to be a solved problem with the introduction of the barrel recoil. The successor was even worse; 4°! Clearly, nobody was anticipating or understanding the utility of being able to react quickly to calls for indirect fires and was in a position of decisive influence at the same time.
Another weakness or such cannons at that period was the widespread use of shrapnel ammunition. This meant the shells needed elaborate time fuses for any hope of accurately timed shrapnel release. A bit too early or a bit too late and the shrapnel shot was quite useless. As a consequence, shrapnel was indeed quite useless in most engagement. You simply couldn't get the timing right. Many fuses weren't even accurate enough if you knew the perfect timing!
Next weak spot: Assuming a good maximum elevation, you'd want to make use of it on more than long range shots. As mentioned before, HE shells produce the best fragmentation patterns if they fall to earth almost vertically. This happens only if they were fired at high elevation angle. Howitzers vary the strength of their propellant charge to make use of this effect even on short ranges. The cannon had fixed ammunition with fixed propellant strength.
Maybe you think that it's not possible to vary the propellant charge in a cannon, but a cannon can be turned into a cannon-howitzer (more usual term is AFAIK gun-howitzer) by simply using semi-fixed cartridges. Those are cartridges where you can detach the case with the propellant, adjust the propellant strength and re-attach the case to the shell again.
Then there's another issue with ammunition: The shells were made of rather soft iron. This produces impressive large fragments, but only few of these and irregularly so. A much better frag pattern is possible with harder steel. This also allows for thinner walls and thus more explosive content and force. Oh, and it would have been possible to add engraving on the interior in order to make the frag pattern even more regular and effective.
Next issue with ammunition; driving bands. Copper driving bands were incredibly expensive, for copper was in short supply. Soft iron proved to be a fine substitute in time for WW2; engineers might have figured this out earlier if more attention would have been paid to the military-economic challenges of industrial warfare before WW1.
Another ammo-related issue: The cases were AFAIK made of brass (copper and zinc). Again, later research yielded perfectly fine lacquered steel cases.
Finally the shell size; due to lack of interest in squeezing out a good range, shells were commonly of a very poor aerodynamic shape. The armies of WW1 only introduced superior shell shapes in about 1917, yielding about 15-20% more range with the same propellant and barrel.
It's astonishing that most reports about ammunition supply shortages in the Germany of 1914/1915 focus on the availability of nitrogen (previously made of imported saltpetre, during the war exclusively made with synthesizers that used the 80% nitrogen in the air). The use of synthesized nitrogen solved the ammunition crisis of 1915, but it also contributed to the famines of 1916 because the agriculture needed nitrogen as fertilizer.
It appears the entire ammunition was about the use of scarce or wrong materials.
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Maybe you think they couldn't have done better with the technology of their time, but the ammunition-related issues were all about paying attention to them in the first place and there was in fact a vastly superior gun concept:
|Cannoni da 75 Mod. 1911 Déport|
It introduced the revolutionary split trail (54° traverse!) and featured a fine maximum gun elevation (not sure if 45° or 65°). This allowed even for a secondary use against aerial targets (most importantly the rather easy shrapnel target of tethered artillery observation balloons).
The difference between a really well-done light field artillery piece and what was in service in the thousands is astonishing. It's yet again a reminder about how poorly even the great powers were prepared for a great war in 1914 after up to 43 years of no involvement in European warfare and just a handful to dozens of expeditionary/colonial wars for two generations.
Now guess what time period does this remind me of?
Now guess what time period does this remind me of?
P.S.: I wrote this in mm instead cm. Not sure what was preferred at the time, maybe cm. "7.7 cm" is still awkward to me, as in German we'd actually write "7,7 cm" and no-one really needs this confusion..