Soft recoil artillery, and electronics-coined artillery in general

"Soft recoil" mechanics have been one of the no-breakthrough evergreens for generations. Again and again developers looked at it, trying to make it work competitively.

Soft recoil lets the bolt (in a rifle) or entire barrel slide forward at the moment of ignition, so the forward momentum cancels much of the recoil. This allows for more controllable fully automatic fire (as in the Singaporean Ultimax 100 light machinegun) or allows for a much lighter carriage, maybe a much lighter platform vehicle.

The first notable and till today probably most successful soft recoil artillery piece was a pre-First World War 65 mm mountain gun. It was evidently useful, for it was still being used post-WW2.

A much more modern attempt was the American XM204:

A German arms museum (WTS Koblenz IIRC) has one XM204 prototype and its plate is rather dismissive, pointing out that it failed the very same way other soft recoil gun designs failed as well; timing the ignition. Range dispersion was intolerable.

Now fast forward to 21st century, and range dispersion is curable. Trajectory correcting munitions are fired at a point behind the target, and the munition deploys a brake (not real steering) at the correct time to correct the range. This doesn't change the left/right dispersion (I keep forgetting the terminology for this).
One method to determine the correct timing for the brake is to track the munition by radar and initiate the brake with radio command - this has been done with multiple rocket launchers. Another way is to use shock-hardened, very compact inertial sensors or satellite/radio navigation. This kind of trajectory correction can nowadays be compact enough to be built into a standard fuse (patent example here; I've seen even simpler-looking, actually-built devices). This leaves no room for great fuse functionalities, but it works apparently.

Maybe in combination with this the newest attempt to revive soft recoil artillery may actually make sense:

(0:43 sec; the forward movement of the barrel prior to firing.)

edit: Additional video, explaining it a bit more

As of today, the latter video had 1,528 views after almost ten months on Youtube. That's a rare case of an American company developing some gun and (almost) nobody paying attention. More videos here and here.

The accuracy of the launcher becomes less important if not irrelevant if electronics and movable surfaces have the last say on external ballistics. This is a bit reminiscent of fighter agility becoming less important since missiles have become very, very agile (ever since the R-73 innovation).

The possibility of using lightweight platforms for artillery ordnance is but one consequence of many. The electronics revolution in artillery is bound to change artillery a lot in comparison to 1980's hardware. This has so far not really happened, as 1980's and older equipment has been maintained and upgraded or new equipment based on late Cold War requirements has been introduced. The great fashion of the post-Cold War era was air-deployability and wheeled platforms. Neither aimed primarily at exploiting electronics advances, but at suiting better for occupation and intervention warfare.
Vertical launcher and fibre-optic guidance artillery haven't made it into service so far, both are apparently much sexier than superior in practical employment. 

Some artillery requirements which do deserve much greater attention and emphasis are in my opinion
(1) Super-quick reaction. A firing mission sent by radio to a computer needs to be executed within seconds, as many targets are fleeting. A howitzer of traditional design with only 50 or 60 degree traverse is too slow if the firing mission isn't within this traverse. The 1960's D-30 was superior in this regard. Most self-propelled howitzers have 360° traverse, but some -notably most on wheeled vehicles- don't.

(2) Ability to hide behind concealments such as buildings without great impediment of capability. Traditionally this has been an issue about maximum elevation angle; the upper angle group (45-70°) that's now standard for howitzers was early on in part a requirement for enabling fire from within woodland (clearances, from woodland roads et cetera). Nowadays we could have a simple camera sensor looking all-round and determining the actual horizon (such as 3,600 traverse/minimum elevation combinations) and transfer the info to artillery fire control centre so it can have all SPGs hidden, but also arrange for sufficient area coverage of the fields of fire. This is behind the scenes stuff, of course.

(3) Covert, camouflaged AND deceptive modes.
covert - looking like a mobile civilian object, such as an abandoned long ISO container
camouflaged - classic approach, but not necessarily woodland camo. Settlement environments should be considered for camo pattern. A reduced radar cross section might also help against aerial ground moving target indicator radars.
deceptive - look like a stationary object (such as a hut), and on road marches even tracked SPGs should not be identified as tracked vehicles by ground moving target indicator radars (which can usually tell tracked from wheeled).

Some old requirements such as NBC protection (air filter and internal overpressure compressor) may be unnecessary now, but it shouldn't hurt too much to keep an upgrade option for it ("equipped for, but not with").

I mentioned before that the ban on most cluster munitions in most countries is a powerful argument for going back to smaller calibres, such as 105-122 mm (more efficient in terms of fragmentation-saturated area to HE shell weight).

related: 2011-10 "An article about artillery",
Defence and Freedom's general arty blog post

edit 2015: http://www.mandusgroup.com/downloads/Hawkeye_105mm_Brochure.pdf


  1. The term you are looking is "dispersion in bearing", as opposed the "dispersion in range" one typically gets from less than precise fusing and small range errors.

    1. That and "deflection" appears to be used for this as well.

      A major driver of dispersion in range are AFAIK irregularities of the propellant.

  2. While this may be doing unnatural acts to a flea, the distinction between deflection and dispersion are important. Deflection is a force that moves the mean point of impact, it is consistent and be compensated for by aiming once discovered it is not random. Dispersion happens around the mean point of impact, it is effectively random and can be only controlled by greater consistency of shot performance.

    1. Dunno what you mean with flea, but "deflection" is being used to describe the let/right dispersion. It's confusing since "deflection" is also being used for shooting with lead at a moving target.

      "Range Precision PE: .35% (assisted), .30% (unassisted) of range
      Deflection Precision PE: 1 mil (low angle), 2 mils (high angle)
      Accuracy: 200-50 meters CEP, at 25 km w/ 20 km Met separation."

      source http://www.fas.org/man/dod-101/sys/land/lw155.htm

  3. Trying not to be pedantic ( see flea reference above, sorry if it didn't come across). After looking at the link I believe we are talking about the same thing. What is being measured by the FAS link is precision, effectively it is the same as dispersion but unfortunately the terms are different. Precision measures how consistent an event is (doing the same thing over and over again), where accuracy is conforming to a standard.( hitting a target or point of aim).

  4. Accuracy is the average location compared to the intended location of impact.

    Dispersion is how much the actual impacts differ from the average location. Dispersion can be measured CEP-style, but with artillery it's usually measured by stating the maxima save for very few exceptions (IIRC).

    The whole thing gets even more complicated by artillery/mortars having additional terms for describing the danger zone in which friendlies shouldn't be.

    My point is that the dispersion left/right has apparently varying terminology in English; I've seen the 'bearing' terminology, the 'deflection' term and IIRC even a third one.

  5. 'A German arms museum (WTS Koblenz IIRC) has one XM204 prototype and its plate is rather dismissive, pointing out that it failed the very same way other soft recoil gun designs failed as well; timing the fusing. Range dispersion was intolerable.'

    Would this observation hold true with the high impulse weapon system (http://youtu.be/HyAl9qK3Rlg)? If so, then we are limited to direct fire missions at no more than 2 km distance... Even so, you could still get some impressive infantry portable weapons out of that: Maybe a 25mm tripod mounted cannon, or a 75mm mountain gun?

    1. Long story short; a weapon like that would be thrown off aim if much of it suddenly moved forward prior to ignition. This would double action triggers make look accurate.

      For a portable 75 mm mountain gun, look at this
      and remember the originally high hopes for mountain guns with a recoilless gun principle...

  6. To the best of my knowledge, the HIWS doesn't use a countermass system, but a design that allows for a much longer path of recoil. Thus, there isn't the sudden massive spike as seen with conventional guns. If implemented in howitzers and cannons, weight could be reduced to levels that were previously unsafe.

  7. Maybe you are interested in the video (see at the end) of the Canon de 65 M (montagne) modele 1906, which was uploaded after this blog entry. Slow-motion helps to some degree to appreciate the details of action even if it is limited by the - understandably - slow frame rate. Still a great video, link below.

    It is quite astonishing that this out "soft-recoil" mechanism was developed and put into service within just a decade of the French 75mm 1897 with it's hydro-pneumatic recoil mechanism.


    P.S: Shouldn't modern electronics (well decades-old would also do) also (greatly?) reduce the negative impact of the forward-moving barrel on dispersion/deflection?

    That said other factors are of greater importance, but it is still a neat niche.

    Link: https://www.youtube.com/watch?v=RmX9DeSZWZA