Improving The AK’s Accuracy, 1950

ak-brakes

The constant bugbear in Soviet small arms engineers’ sides after 1950 was the poor performance of the AK rifle in fully automatic. The rifle was for decades very inaccurate in fully automatic fire, owing to its vigorous action and relatively (when compared to pistol rounds) powerful round. A wide variety of approaches were taken to try to mitigate the dispersion in the automatic firing mode, and a Russian blog post covering some of the earliest experiments has been translated by Ensign Expendable of the Soviet Gun Archives blog:

The accuracy of an automatic weapon is important, and many experiments were run on the AK platform to figure out if it can be increased. A number of experimental muzzle devices were built for this purpose. _tezka provided this picture.

Left to right: similar to stock type, brake-compensator, two chamber, flash suppressor, single chamber, reactive.
While all of these successfully reduced muzzle climb and improved accuracy, there was one important drawback that engineers did not necessarily consider…
“The positive effect of the muzzle brake on the accuracy is at odds with the negative result of the sound wave hearing, which is greatly increased to unacceptable levels with most muzzle brakes.
The evaluation of the effect of the sound waves on hearing reveals that all muzzle brakes in the table result in a bothersome or painful sensation in the ears.”
A DShK style reflector was considered to remedy this effect, but…
“…a reflector of such size can hardly be recommended as they decrease the maneuverability and comfort of the weapon and do not achieve the intended result of reducing the sound to a level that does not cause pain.”
Another device was tested to improve accuracy, but it was a different kind of brake.

 

Curiously enough, it was a brake for the bolt. The experiment was meant to determine the effect of the speed of the bolt flying back and forth on accuracy. The knobs on the sides could adjust the force applied to the bolt in order to slow it down.”

 

The criticism that the AK’s action is violent was not lost on Russian engineers; the last experiment detailed in the post was an attempt to slow the bolt carrier down during operating, reducing the elastic collision of the bolt carrier bottoming out at the rear of the receiver as much as possible while preserving reliable functioning.

While the later AK-74 would introduce a specialized muzzle brake to mitigate this undesirable characteristic of the Kalashnikov design, the rifles still did not quite live up to Soviet, and later Federal Russian standards for full auto accuracy. As a result, the Abakan trials were held, which resulted in the abortive adoption of the AN-94 rifle by the Red Army in the late 1980s, and later to the balanced-action A545 rifle that passed state trials late last year.



Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.


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  • iksnilol

    What about an adjustable gas system? Would that have helped? Since IIRC the AK is overgassed by default.

    • MPWS

      Very true; this is what was done on FAL and worked extremely well. But look at complexity – and cost. I was amazed and impressed when I first studied FAL. I still like it a lot.

      • iksnilol

        Is an adjustable gas system that complicated? Since I know people have made them.

        • MPWS

          On original FAL, yes it is – you need to see engineering drawings with tolerances to appreciate it. When made individually, some short cuts can be possibly made, true. Same time it does not mean the AK’s version has to be the same; there is always space for ingenuity.

          • iksnilol

            On FAL I don’t know, haven’t taken one apart. But couldn’t you make a simple adjustable gas block for an AK? Something using a gas screw. I know I saw a guy online make one out of a Yugo gas block (the one with the shutoff valve).

          • MPWS

            I would attempt to insert rotary orifice between piston and cylinder in such a way as to allow variable inlet (volume) of gas. than of cause you need a reliable detent of sort.
            This would be interesting project I would not mind to take on but it requires two things: gun to play with AND proper machinery. It would have to commence by analysis of parts strength and engineering layout. I suppose 2 positions might suffice at start.

          • Scott Tuttle

            how about just increasing the strength of the main spring. that would inhibit gas flow with the piston.

          • MPWS

            Power (preload) of drive spring with rifles generally does not count as means of piston resistance. It has more to do with ability to hold action safely forward and to strip a shot from full stack, but it does not have ability to oppose force of piston.
            We are talking couple of pounds force versus hundreds of pounds from piston.

          • Scott Tuttle

            from what I saw in that video posted up above it’d take a lot more to make it more accurate under full auto than gas restriction anyways.

    • Esh325

      I’m sure they tried gas regulators, but I imagine it still didn’t give them the desired effect.

      • iksnilol

        I just plan on going suppressor + adjustable gas system for my AK when I get one. Should be decent enough, especially with the extra weight of the RPK receiver and barrel (shortened RPK barrel to 30 cm is the plan).

  • Pete Sheppard

    VERY interesting! Thanks!!

  • MPWS

    This is what it takes to have full reliability, at least by 1950s standard.

    First thing, which hits you eye when you look at AK action, is proportion of primary vs. secondary mass – it’s impressive. The second is diameter of piston; system would probably run as well with significantly smaller one. Muzzle brake is good, but you have side-blast which your buddies have to live & die with. These are factors to consider and do something about at first place. But now, who cares; its a piece of history.

    • The mass ratio of an AK is about 5.3, which is very impressive (though it’s worth noting the AR-15 is about the same). I suspect the overgassing of the original AK was an effort to ensure reliable functioning in the necessarily crudely finished magazines they were using.

  • Don Ward

    Oh sure. If you want to trust SOVIET documents and EnsignExpendable’s PROPAGANDA. I see you have finally exposed yourself COMRADE!

    • Zugunder

      I think your caps lock is alive!

  • Esh325

    Problems with accuracy in fully automatic wasn’t a problem unique to the AK necessarily, it’s just the Russians put more time into it than most countries. It’s a problem with most assault rifles. With controllable automatic and burst being a big reason to adopt the 5.56×45, a lot of countries figured out even the 5.56×45 in a conventional rifle design still had too high of shot dispersion in automatic fire. The AK-74 is probably considered more controllable than most assault rifles, but to the Russians its performance still was poor, hence the development of AN-94 and other balanced recoil designs the AK-107. The AK-12 is suppose to have much better performance than the AK-74 in fully automatic

    • MPWS

      Plenty of video from current E.E. conflict seem to support your view – the AK74 is lot more stable at burst. This is primarily by lesser impulse cartridge plus muzzle break.

      What is interesting and you correctly mentioned that, is that Russians do not contend with past standard and try instead to improve on it. Of course, there is penalty – in terms of complexity and cost. It’s all compromise, isn’t it?

      My personal view is that AK74 is plenty good in current form.

      • Esh325

        Thanks. I suppose the issues with the ak74 is that the Russians wanted something that could take modern attachments more easily and improved ergonomics, but redesigning the ak74 into the ak12 than just modifying the ak74 seemed a better way to achieve that.

        • 5.45

          Hmm…
          intresting =)
          Most people in the internet nowdays thinking that “tacticool” look is more important=)
          Yes, it was easier to make AK-74M mod.2 or whatever, but Zlobin is not seeking easy ways.

          I don’t know, how did they manage to make ak-12 lighter, but simple logis says – lighter bolt carrier group.
          So – reliability will suffer.

  • dan citizen

    Fascinating article.

  • Mystick

    After seeing an AK firing full auto in slow motion(it was on an R. Lee Ermey show Lock N Load), I completely understand why it has accuracy problems in those conditions. The entire gun was rippling like a wet noodle, something the AR/M4 platform did not do.

    This isn’t the video, but it demonstrates the principle ..

    • Even the barrel flexes

      • iksnilol

        That flexing is advantageous, the gun flexes to disperse the energy instead of the random energy affecting the bullet 😛 /sarc

        Problem with AK IMO is that the barrel is too thin, that’s why the 5.45 and 5.56 versions are more accurate. Since they have thicker barrels.

        If you want a good AK, build one with a RPK barrel and chop the barrel to 30 cm (if you want to pay SBR stamp) or chop it down to 40 cm if you want to avoid SBR.

        • Yallan

          Shouldn’t be seen as a problem anymore, since Norinco/Chinese Type 56 the most popular AK type has the 1.5 mm thick receiver of the Russian RPK. The only problem is the extra weight.

          • iksnilol

            Are you sure that is the most popular one? They seem good if you ask me. My plan in the future for an AK is to just get a RPK and cut down the barrel (to 30 cm) and then permanently add a telescopic suppressor to get minimum legal length. By my math it shouldn’t weigh much more than a standard AK if I go with titanium suppressor and standard non-RPK furniture.

            What I am more interested in than the thicker receiver is that the Type 56 also seemingly has a thicker barrel. 7.62×39 AKs have way too thin barrels.

        • mosinman

          Or just go with the superior VZ.58 😉

          • Big fan of the 58, but even I’ll admit the AK has some major advantages, mechanically.

          • mosinman

            The only thing I can come up with off the top of my head is a lower cyclic rate and ease of manufacture. Unless you’re talking about the ejection port.

          • Anti-pre-engagement, clearer feedway, and the locking surfaces can’t erode the receiver if it’s not heat-treated properly (though really bad things do happen if an AK’s flat isn’t heated properly).

            The mags of the Vz. 58 were a big plus for a long time. Definitely some of the best-designed magazines of any Cold War rifle.

          • iksnilol

            What advantages? I am a bit curious since I don’t have any experience with the VZ58. At least, I haven’t handled one or disassembled one.

          • iksnilol

            Trust me, I would if it used AK mags. Chop the barrel to 30 cm and shorten the gas system (if necessary), add telescopic suppressor. It would be a nice and lightweight rig.

          • mosinman

            It would be interesting to see an attempted conversion to AK mags or converting AK mags to work in the 58. I imagine you wouldn’t have to chop too much as the VZ58 is a handy and short rifle. Either way I really like the position of the 58’s fire selector and the last round hold open, those are major bonuses in my opinion

          • iksnilol

            If converted to AK mags I doubt the last round hold open would work anymore. Unless you used Yugo followers in the mags.

          • mosinman

            It would. But that’s the trade off you make

          • iksnilol

            Yes, but you could possibly make the BHO work with the Yugo BHO magazine followers.

      • Vitsaus

        Thin stamped receiver, plus a thin barrel, plus enormous bolt carrier. I’ve seen footage of the milled receiver models fired in slow motion and there is much less of this effect. Some of the most accurate military rifles tend to have machined receivers. If you’ve ever read the book “The Gun” by Chivers, he pretty much confirms that the soviet authorities comprimised on accuracy and the bolt hold open in favor of easy production.

        • Unfortunately, there were enough liberties taken by Chivers in writing The Gun that I don’t feel it can be taken, as a whole, as an authoritative source. I was very disappointed by it, when I read it several years ago.

          • Vitsaus

            Hm. I think its pretty obvious why you didn’t like that book.

          • Man, if enough primary sources contradict what the man wrote in his book, what am I supposed to think? “Oh that’s OK, I’m sure Chivers is right because LWRC’s marketing material says DI sucks!” Give me a break!

      • Kelly Jackson

        Every barrel flexes.

      • iksnilol

        Also, if you see slow motion videos of ARs firing you will see the barrel flexing about just as much. though many videos focus on the receiver.

        Would post a link/picture but then the comment would have to be approved.

    • MPWS

      Whoa…that’s good one. Here the flimsiness of stock is clearly visible. On another video I saw, the entire receiver was twisting and bending (made of 1mm ridiculously thin sheet as opposed to guns made by Zastava or RPK receiver which are 1.5mm). This is together with ‘over-gassed’ system evidently inherent flaw of AK design.

      On the other hand, the complex AR-type forged receiver is not necessarily answer either. I believe, appropriately thick aluminum alloy, extruded receiver might be the solution; something of what FN does and B-T is doing lately.

      • Extrusions as they are currently being used are way too heavy; you’re getting rifles in the 8lbs unloaded range, which is just ridiculous for a 5.56mm weapon (the B&T is a particularly egregious offender). Forgings are the way to go, IMO, but you have to be able to pony up the money for them. They’re not overly complicated but the startup costs are considerable.

        Without that, you get overweight weapons that offer nothing over the current standard.

        • MPWS

          I happen to have a case study I play with. Complete receiver with charging handle subassembly (length about 10 in) complemented with optical rail weighs at around 1 lb. Previous design out of steel stamped metal was at almost 2 lbs. Aluminum, if used wisely is super adaptable material – 2.5 time stronger than steel at same weight. Extrusions are easy to make.

          At the same time it ought to be mentioned that weight at around 7.5 lbs (3.5 kg) is probably acceptable. Think of purpose of rifle and what is used for. And, more weight, the less of movement when you fire it.

          • I don’t really feel a weight above 7lbs is very acceptable; at that point you’re still 18% heavier than a base M4. That might not sound like much, but considering how heavily accessorized military rifles are these days, I would want to keep weight to an absolute minimum.

            And there’s no question that we can do that – we do it with aluminum forgings.

          • iksnilol

            Okay, not an engineer here so bear with me. Same receiver, how heavy would it be if you went with a forged version?

            I am thinking you can save weight with the barrel, something like the Lothar Walther ultralightweight barrels (thin steel barrel with thick aluminum jacket over it).

    • An AK is after all basically a giant spring accessorized with many smaller springs.

      • roguetechie

        I have two responses here I’m going to try and smash into one super post.

        1. Receiver flex: The Finns actually built and sold a stamped receiver that had reinforcements strategically placed which gave nearly the same performance as milled receiver variants. Also of note is the vz-58 which even though it had a milled receiver is a full pound lighter than a stamped AK when both have loaded 30 round magazines.

        2. Adjustable regulators: If I wanted to add one I think my first choice would be the RPD 3 position regulator. In general I think it would be easiest to adapt since it’s set up for 7.62×39 already and in general I have learned the hard way that the more your donor part diverges in design generation country and for cold war era arms Warsaw or NATO school of design.

        • John

          >I have learned the hard way that the more your donor part diverges in
          design generation country and for cold war era arms Warsaw or NATO
          school of design

          …the more your weapons don’t work?

        • If milled receivers give any gains in accuracy, it’s beyond the level attainable by normal military small arms, anyway. That’s my experience.

          The comparison in loaded weight is overwhelmingly due to the Vz. 58’s aluminum magazines. Unloaded, the ’58 is just a little lighter, which is still impressive.

          I don’t really see the case for a regulator. The most successful weapons tend not to have them (big exception being the FAL), and besides a setting for suppressed and a cut-off setting for firing rifle grenades, they don’t seem all that useful to me when attached to a good design.

          • roguetechie

            Nathaniel,

            On the adjustable regulators I agree with you, but only because the overwhelming majority of soldiers, LEO’s, and even the civilian firearms community do not have the knowledge, self discipline, pride in doing things well, and or the drive to obtain said things. So as of right now, yeah you’re mostly right but still kinda wrong lol.

            However I’m glad you replied to my comment because it allows me to bring this up and get your input. The position you took is a commonly held belief currently, but to me it reeks of lowest common denominator engineering (or to put it another way, the we don’t keep score everyone is a winner participation medal school of thought). Part of what attracted me to the gun world was it’s strident refusal to concede to this corrosive culture that is a monument to mediocrity! (explains why several companies can and do charge $1800+ dollars for a 50 year old gun shoehorned into a new body kit made mostly of parts made on the same machines that produces things like rain gutters and get away with it eh?)

            Another great example of this phenomena is the admissions of many people with real world knowledge and experience that our belt fed weapons are nearly always used like oversized rifles currently…

            I see MULTIPLE reasons that this is occurring but I’m not going to touch most of them. One I will touch is the very prevalent attitude that being a soldier is a JOB you do to position yourself for a REAL CAREER! The problem with that is people don’t dive into the pool of knowledge and immerse their selves in all things military if it’s JUST A JOB! So right there we have all the problems and disadvantages of a conscript force with the overhead and logistical tail of a division level glamper outing!

            Oh oh and nevermind that recruiters warn you REPEATEDLY that mentioning you so much as HAVE AN INTEREST IN FIREARMS could be detrimental to your ability to successfully enlist! Further when your jaw is on the floor many will flat out admit that the army PREFERS recruits that have never even been in the same room as a working firearm much less actually fired one!!!

            So basically what I’m trying to say is the modern world is tailored for the mouth breathing helmet wearing short bus riders, but that is really just even more reason for the firearms community to buck the trend rather than follow the trend.

            WAR is an extreme sport! Hell even owning and using guns recreationally has the potential to be tragically lethal if discernment and a laser focus on safety AT ALL TIMES is not maintained by everyone who is there!

            Honestly the AR 15 is almost always more accurate than 95% of it’s users (including myself… I’ve been very disappointed with my long range performance lately!)

          • iksnilol

            AR-15 accurate? Yeah, but I doubt it can outshoot your average DFS shooter here in Norway.

          • I’ve heard your central argument many times. Fundamentally, users of firearms should be well-trained, but at the end of the day, your small arms must be designed with the user in mind. Many will be quick to claim this sort of engineering is “lowest common denominator” engineering, but that’s not really convincing. Nobody wants to be told that in combat they won’t hit the target 99% of the time, especially if they’ve trained enough to make that figure as low as possible. What if it’s true? There’s a lot of information out there that says it is true, like it or not. So then would taking this into account be “lowest common denominator engineering” or just operating under appropriate assumptions?

            Gas regulators… Be honest, have you ever shot a gun hard, had it start running sluggishly, and then tried to use the gas regulator? I have, on both ARAK-21s and FALs. Gas regulators get HOT. Once you’ve been shooting your rifle for a while, it’d better be designed to run without the user fiddling with that thing.

          • roguetechie

            Oh I agree with you on adjustable regulators being basically useless in combat on light weapons man …. They’re a perfect example of about a MILLION ideas that in theory should be a huge improvement to firearms tech that don’t work how they should… Except I’ve never seen the regulator’s purpose as for changing settings once in combat. From as far back as I can remember I was taught that if you change basically ANYTHING on a gun, car, jet ski, lathe, atv/motorcycle or anything else you ALWAYS take it out to dial it in, and confirm it works well before you trust your livelihood life or both with it again.

            So I personally don’t have a firing range in my basement like Tom Clancy, pretty sure you don’t either. Where adjustable regulators actually help especially now is in helping the shooter get his gun set up after changing parts to work well with the new setup… The most glaringly obvious example of this is suppressors.

            Question?: How many civics would Honda have sold if the carburetor back in the day couldn’t be rejected, if you needed expensive Honda only tools and proprietary manuals, and or had to pull the engine out and buy a new engine?

            It’s not 1952 anymore why shouldn’t we expect manufacturers to actually build guns that don’t require 40% of the purchase price in aftermarket replacement parts to make the gun decent? And going back to regulators … Since the majority of firearms owners in the US have to drive a considerable distance to an outdoor location to legally do our dialing in shooting and it’s usually either too hot or too cold… A toolless adjustable regulator seems like it would be a pretty reasonable feature to ask for. Hence my lament about lowest common denominator engineering.

          • I condoned the addition of regulators as either devices to improve operation with suppressors or as gas-cut-offs for launching rifle grenades.

            I don’t need to have a secret range in my basement to have shot an FAL. The regulator gets hot, and pretty much de-facto is useless as an “adverse” condition setting. The only conceivable benefit to it in that respect is as a “cold weather” setting; that I buy as being potentially useful, though I think we have cold weather operation pretty much licked at this point.

            What about a Colt 6920, Daniel Defense DDM4, BCM, or Spikes isn’t satisfactory out of the box? I’ve shot my 6920 at -30 degrees, and I didn’t have any problems, and I wasn’t using 5.56mm either.

          • roguetechie

            Nathaniel,

            . I think you missed my point pretty majorly here. My point was that as far as changing settings midstream goes I 100% AGREE with you!

            . Honestly if we need that type of functionality, a new way to get it would probably have to be found.

            . Now the Col weather and basement firing range comments were meant to illustrate the way an adjustable gas regulator would be great for a modern firearm. So basically I see the main purpose as allowing”hassle minimized” fine tuning of your firearms after a parts swap, suppressor addition or removal, or etc. And since most of us don’t have a way to shoot in our basement or really anywhere within a half hour drive of our homes, it seems logical to me that the less tools and other paraphernalia you need to bring in order to do all of this.

            Also I’d like to note that I recently read about the very cool firing range Tom Clancy had built in his basement, and his drool worthy guns lol. Hence the mention of this.

            Also much of my post as with almost all of my posts was primarily meant to encourage people to start examining WHY they do things the way they do! Critical thinking skills and rational evaluation of the people platforms and processes governing their current endeavors are vital no matter what you’re doing.

          • roguetechie

            So my contention was that adjustable regulators are primarily useful for dialing in a firearm for a specific parts configuration and or ammunition combination. The basement firing range and sub zero temperature came in because for almost everyone I know it’s a 45-120 minute drive to the ranges we can afford to use with any sort of regularity, and to me that makes a toolless adjustable regulator very desirable for those quick midweek sprints to the range to make sure the gun will behave when you really need it to that weekend!

            As a side note it would be nice to have a happy medium between RFB that has too many settings plus is too finicky to be useful as a combat arm, and the standard 2-3 setting regulators we see otherwise. Or maybe something like HK does with the roller contact surfaces and the lee Enfield did with bolt heads to deal with receiver stretch could be done, and either offer a variety of different inserts that you can drop in allowing x number of fixed settings. Or if the company that makes the regulators open sourced that part and provided key dimensional and other data plus a small number of “known good” options which they make and sell, and a partnership with a place like gunco that creates a sub forum for people to share the results of the homebrew adjustment plates they have experimented with. Of course with something like that the issue you run into is how exactly does a company provide a warranty for people who don’t experiment while also not being taken for a ride by dishonest experimenters?

            I think we fundamentally agree on this subject, but we both approach it from different angles. I apologize if I was overly antagonistic.

          • No need to apologize.

            In theory, I agree with you, but my experience with regulator-less firearms is that they work well even with underpowered ammunition and even in cold conditions. While I could conceive of a situation where maybe a regulator might be useful, that in and of itself doesn’t make a compelling case for them, and certainly doesn’t hold much weight against the added complexity and cost that they come with.

      • Mystick

        Don’t forget cables!

  • Y-man

    In Soviet Russia, gun hears you.

  • Lance

    The results of these test in the 50’s as well the need to keep cost for production down resulted in the adoption of the AKM and eventually its numerous slant break. AK-74 is very very controllable on full auto. Think the AK-74 is just as is to me.

  • gunsandrockets

    With such poor control in full auto, the AK-47 hardly has any advantage over a SMG.

    • iksnilol

      Much more range than an SMG I would dare chalk up as an advantage.

      • gunsandrockets

        Only in semi-auto. Practical full auto range is probably greater with a SMG because of smaller dispersion.

        • iksnilol

          I doubt anyone uses full auto at farther than SMG ranges (except for MGs and the like). Even with ARs and 5.56, who shoots full auto at 300 meters?

  • Adam aka eddie d.

    That “bolt brake” on the last picture seems very interesting.
    I assume the balls were some sort of pressed in free spinning rollers,
    like detent balls or roller ball attachments in some measuring tools.

    The result would’ve been slightly similar to what the roller delay does in the G3/MP5 actions, only it was supposed to limit/settle vertical movement,
    not delaying bolt movement time. Very simple, very Russian solution.

    The more I learn about Russian firearms technology the more I respect their engineers.
    They’ve always solved problems in a very simple (often downright crude),
    but very effective manner.

  • Karbar

    Fascinating Russian ideas.

  • John Daniels

    It surprises me a little that they didn’t put some kind of super basic, short, fat, silencer on. Such a thing can be made relatively easily and cheaply out of stamped steel on a massive scale. Seems like it would’ve been a fairly simple solution to several problems.

  • 5,45

    Yep, righ on spot. There are couple of methods to measure full auto dispersion in our firearm science.
    Intresting, that whenever I’ve tried to ask H&K engineers about G-36 or HK416 accuracy in fa mode – there was no answer.
    And that’s bit strange,’cause our firearm “school” and history is based on german base (WWII experince).

    it’s easy to check one.
    One of the methods
    3 positions (lying unsupported, kneeling, standing), 10 short bursts, 100 meters
    using irons
    ideal fa dispersion – 50% of holes in target should be inside square with size 45×45 cm and better
    AN-94 makes it easyily

  • Zaza Pensive

    My view is that the design engineering for the forces in most semi/auto.rifles isn’t well thoight out….The reaction force composite should go directly to the rear 180degrees.from the shell trajectory. ….other vectors cause the move of the barrel off target.

  • MR

    Russian automaton spam droid…totally relevant to the conversation at hand!

  • MR

    WHAT??!? (HE SAID “LOUD!!”!!!)