Garand vs AK, piston location

[chris in va]

Here I am 'inspecting' my Garand and being the analytical type I couldn't help but ponder the differences. Any particular reason why Kalashnikov (and Simonov) placed the piston on top? The Garand's barrel is much closer to the sight plane.

[BluRidgDav]

Because Kalashnikov was designing a fully-automatic weapon, he needed the barrel to be lower, and more in line with the recoil forces that would be transferred back through the stock to the shooter. Despite the reduced power of the Russian 7.62x39mm cartridge, as compared to the American .30-'06 (7.62x63mm) round, fully-automatic fire would have been uncontrollable, if the AK's barrel was above it's gas cylinder, like the M1. The US learned this the hard way, when they designed the M14 to be "capable" of full-auto fire, but, not very practical to use that way. It was made even worse, by the power of the .308 (7.62x51mm) cartridge.

Note that Eugene Stoner also designed the M16 with the barrel below the gas tube of his direct impingement system. While this also placed the M16's sights over 2.5 inches above the bore-line, as compared to the Garand's sight height of approximately 1 inch, it placed the M16 barrel in a straight direct line with the stock and shooter.

When it comes to controlling recoil, higher sights are less important, than a lower barrel.

[HiBC]

Some distance of line of sight above line of bore is quite practical in terms of useful trajectory.

I do not intend that to be a negative about the Garand,they shoot just fine.

[Destructo6]

I'd imagine that the over the barrel gas system simplifies a lot of things, by being up and away from other things that are harder to move.

The gas piston/op rod has to dog leg at some point to clear the magazine. On the AK design, it's a straight shot to the carrier and that's easier to manufacture, too.

[tahunua001]

over the top makes for easier maintenance and easier recoil.

[Bart B.]

Some distance of line of sight above line of bore is quite practical in terms of useful trajectory.

Never heard of that. Please explain why.

[dahermit]

Because Kalashnikov was designing a fully-automatic weapon, he needed the barrel to be lower, and more in line with the recoil forces that would be transferred back through the stock to the shooter.

But that does not explain why the SKS (non-automatic), also has the gas piston on the top.

[Bart B.]

dahermit, that may be done to allow only a couple of parts to be different between the semi and full auto versions.

Same thing with the differences between the M14 and TRW making the M14NM version that did not have cutouts in the receiver for the full auto parts to fit in. The commercial version, the M1A, is a copy of the M14NM version which was never able nor intended to shoot full auto.

A presentation grade M14NM was presented to the M14NM production manager at Thompson-Ramo-Woolridge honoring him with doing a good job. The AFT folks heard about it, checked his rifle and immediately confiscated it because ATF agents thought it was the full auto capable M14 and the manager didn't have papers proving he paid the full auto owner tax for it. Took a while, but the ATF was finally proved in error; the manager got the beautiful M14NM back.

[Slamfire]

It certainly made the operating rod easier to make. A Garand operating rod was very complicated and it has to be bent around corners.

Given the gas system of the SKS was successful, I don’t see any reason why the Soviets would adopt something radically different. There are more parts to the AK gas system but I will bet that the total production effort was less than it took to make a Garand gas system or a M14 gas system. Certainly the receiver did not require an expensively machined operating rod track.

Something I did not appreciate, until I read the book "The Gun" by Chivers, was that the adoption of arms in the Soviet Union was a state enterprise and the "best design" really was the best design.

Kalashnikov's design was critiqued by panels of very experienced, very patriotic, Soviet gun designers. Even after it was decided to make the AK the Soviet service rifle, it underwent extensive tweaking by subject matter experts before it was put into full scale production.

[2damnold4this]

But that does not explain why the SKS (non-automatic), also has the gas piston on the top.

The SKS shares a lot of features with Simonov's AVS-36 which was selective fire.

[tahunua001]

dd I mention that it's easier to maintain when the piston's on top?

[Tejicano]

Coming from a degreed mechanical engineer who spent years doing design work it is all about the manufacturability.

Just look at the operating rod on the Garand system. It is non-symetric and its shape bends and twists in every direction. The receiver it runs in is even more complex.

The AK bolt carrier is all but symetrical - other than the bolt groove underneath and the charging handle which is added on after machining. This is one reason why it was manufactured in so many countries - many with only minimal industrial infrastructure.

The Garand might not have even been adopted if it wasn't for the fact that John Garand designed it to be manufactured using the same equipment on hand at Springfield Armory where the Springfield '03 bolt action rifles were made.

Granted, the lower barrel plane does reduce the tendency to rise on full auto fire but having the gas system over the barrel makes more sense. Just look at almost every other successful gas-operated, semi-auto military rifle - FAL, FN-49, AR, SIG, StG-42/44, etc. Heck, even the HK roller-delayed blowback system puts the recoil spring in that same location.

Lots of gas-operated, belt-fed machine-guns have this upside down because the belts feed across the top of the receiver. It just makes things simpler to keep the recoil action on the other side of the design from where the ammunition feeds.

[HiBC]

Its a small thing,and,in the extremes it is not so good,but thinking in terms of what Sierra calls "max point blank",and a +/- from line of sight

The first leg of the trajectory is bullet below line of sight,the second leg is bullet above line of sight,the third leg is the bullet below line of sight.

Within reason,a little more sight height extends the first leg .Not a great deal,but some.

So,if you decided +/- 4 in of trajectory was acceptable,a 4 in sight height would give you a slightly longer "point blank" than a 1 1/2 in sight height.

Its not enough to get real excited about.

And,I'm talking about hitting hair,not x rings. X rings don't have a lot of +/- tolerance.

[Slamfire]

The Garand might not have even been adopted if it wasn't for the fact that John Garand designed it to be manufactured using the same equipment on hand at Springfield Armory where the Springfield '03 bolt action rifles were made.

I would like to believe that Garand designed it based on what equipment was available, but I don't believe that by the time you get to the 30's Springfield Armory had much in the sense of modern production equipment. The last major production facilitization was WW1 and I understand from reading Hatcher's Book of the Garand, SA was re tooled to produce the Garand.

It is my opinion that the complexity of producing the Garand was directly related to the fact Garand was a tool and die maker and when he came to a design problem, the fix was foremost importance, not the production implementation or costs. I suspect that he envisioned a new, unique production tool and process, but he was not a Production Engineer. As you know, special tooling costs a bunch but that was not a real issue at the time. Integrated Product teams came much later.

Now you get post WW2, everyone realizes that requiring special test equipment, special tooling, special dedicated production equipment is not the best way to go.

If you have the time or inclination, and if you have seen it, how do you rate the HK91 roller bolt for ease of production?. This was designed post war by Germans who had gone through the experience of loosing entire Armies in six months, complete loss including equipment. I have heard that the HK91 was specially designed to build quick and cheap, in fact, that the design philosophy was to build them fast and ignore rebuilds. From what I have heard about rebuilding, it is actually quite a labor and material heavy effort.

[Tejicano]

Slamfire,

The HK 91 is basically the semi-auto version of the G3 which is what the CETME became when the ex-Mauserwerke engineers brought production of that rifle back to Germany. I say "back" to Germany because the original design was the StG45 in 7.92X33mm.

I have actually been to the Mauserwerke museum in Oberndorf. One of the questions I had for the tour guide was about the StG45 - he confirmed for me that it did have a fluted chamber just like the G3 and would not function properly until they added it to the design.

The HK91/G3/CETME design is probably one of the best designs from a manufacturability standpoint. IIRC the bolt carrier is a casting with the top tube welded on. There are some rather fine tolerences in the surfaces of the bolt and bolt carrier but a lot of that can be adjusted for by selection of the roller diameter. Probably the most complex part is the fluted barrel.

This design requires a bit more industrial infrastructure to produce than the AK but a few tweeks - like using a pin to capture the barrel to the breech-block instead of welding - could bring that required industrial level down a bit.

Back to Garand - True, the fix is the key but as a tool and die maker he would have a deep understanding about what features of a design would be simple and what would be difficult to produce. He would be the perfect person to design a fix that could be built with the major tools at hand.

I am not aware of what Hatcher said about the start of Garand production but either way I am sure SA would have to procure some amount of new equipment - they may even have rejected some?/most?/all? of Garand's suggested production methods. My understanding was that his design would have had less impact on the SA facilities than any other competing design being evaluated.

[Slamfire]

Thanks for the reply.

My understanding was that his design would have had less impact on the SA facilities than any other competing design being evaluated.

Perhaps you are confusing memories of the adoption of the Garand with the adoption of the M14. Regardless, one must always take into account the Army's bias towards "inhouse" designs versus designs created from outside the Ordnance Bureau. Like every other agency, the Army will stack the deck to get what it wants. In the downselect of the M14 versus FAL, one of the points for the M14 was that it was supposed to be able to use most of the same tooling that was used for the Garand, therefore reducing production facilitization cost. I read somewhere, this turned out not to be true at all, and most certainly not true for TRW, Winchester, or HRA, all of which had to buy their own production machinery. I believe this was a spurious argument to get the Army a rifle that was very similar to the Garand. The FAL was just too different.

If you recall your history, the Secretary of Defense forced the AR15 down the Army's gullet. They had already rejected the AR10 and Ar15.

Being familiar with the predilections of the Army, the user wants something better but only a little different. The Army totally rejects revolutionary change. I believe pointy sticks had to be wrestled out of the hands of Troglodyte Infantry before they would grasp the new issue stone tipped spears, and until they died, retired Troglodyte NCO's would tell everyone that nothing was as ever good as their cherished pointy sticks. You look at the evolution of Army service rifles, from 1761 charleville musket to M14, you can see the little incremental changes. If you noticed, removing the external hammer from the 1861 musket was way too much change. With all the falling block, rolling block, lever action and bolt action designs from which to choose at the time, when the Army is forced to go to a cartridge rifle, it decides on the 1873 trapdoor which is about the closest they could be to an 1861 musket.

The rejection of the 276 Pedersen cartridge falls into the same category as too much change. Which was too bad because it was the right cartridge at the right time. At the time, the justification to keep the 30-06 was because of all the stockpiles of 30-06, which, if you know anything about insensitive munitions, ammunition has a shelf life, and therefore using that as the reason not to change, just shows how bogus the reasoning. Instead, when the Army is forced to go an intermediate round, it is forced to swallow the 223 with the AR15. The 223 is a great round to shoot poodles, but not the big French poodles as the round lacks the lethality to put them down with one shot.

[BluRidgDav]

I firmly believe that if the Garand had been fielded in .276 Pedersen, our troops would still be killing the enemy effectively with it, today. Maybe not in a decendant design of the Garand. But, the cartridge would have carried over into whatever follow-on rifle we came up with. Instead, we continue to search for a replacement for the 5.56mm, while limited to weapons with magazine dimensions built for that tiny round: 6.8 SPC , .300 Whisper/Blackout, .458 SOCOM, the search goes on and on . . . .

[semi_problomatic]

You have to think of the purpose of the rifle as well. The garand was intended for aimed shots. The AR and AK designed for spray and pray type shooting. The M14 was a cop-out cheapo rifle designed with spare parts from the garand with certain complaints about the garand addressed. It was still designed for aimed fire and not full auto control.

[Bart B.]

I thought the only parts common between the M1 and M14 are the rear sight, ejector spring and extractor spring. What other parts are exactly the same?

I think one of the service rifle teams used modified M1 trigger and sear assemblies in M14NM's to be more reliable in those match grade service rifles.

[SR420]

semi_problomatic The M14 was a cop-out cheapo rifle ...

Really?

[Fishbed77]

The M14 was a cop-out cheapo rifle designed with spare parts from the garand with certain complaints about the garand addressed.

Wow. Misinformation overload.

[semi_problomatic]

Really?

From: http://photos.imageevent.com/badgerd...n%20070603.pdf

The M14 rifle incorporates a number of designs borrowed from developmental rifles dating between 1944 and 1954. Essentially, the M14 as known today is a slightly improved version of the T44E4 rifle design of 1954. The T44E4/M14 rifle incorporated the following component designs:
M1 - hand guard and rear sight M1E3 - bolt roller
T20E2 - bolt, firing mechanism, magazine latching system, operating rod, operating rod spring, operating rod spring guide, select fire components and stock
T25 - gas system and combination front sight, castle nut, set screw and muzzle attachment assembly
T31 - magazine
T44 series - bolt lock (T44E1) and receiver (T44E4)
The T25 rifle, including the improved Joseph White gas system, was designed by Earle M. Harvey. Remington Arms Co. developed the T44E1 bolt lock. Otherwise, the component parts listed were the ideas of John C. Garand. He patented the extractor, hammer, magazine, magazine latching system, and rear sight parts.
Denied his wish for a magazine fed rifle in the M1, John Garand’s T31 magazine was further improved by him for the T44E4 (M14).

http://forgottenfirearms.blogspot.co...arand.html?m=1

Look at the T20. The origional t44 (M14 prototype) was a T20 rebarreled and chambered for 7.62x51. It used a short piston and operating rod from another prototype (t47) and magazine block fillers. In case you're confused by all the T's, the t20 was a M1 GARAND prototype to use box magazines

[Tejicano]

Slamfire,

I am certain I was told that Garand's design could be made with the same, or most of the same, equipment that the Springfield '03 was made on. That does not mean that this information was correct. I heard this back in the dim days long before people owned computers, when word of mouth was about all you had if the information was not available in your local library.

Yup, in the Marines in the mid-70's I heard lots of stories about how the M-16 would jam at the worst possible moment and about how most platoons in Vietnam always had one or two hold-outs who managed to keep an M-14. I myself will admit that I still have an affection for the M-14 as it was my first issue rifle but understand that my affection does not make it a better combat rifle. I prefer the heavier round but my go-to rifle is more likely to be a FAL. Weight does not mean that much to a former 81mm mortar grunt.

[SR420]

semi_problomatic Really?

From: http://photos.imageevent.com/badgerd...n%20070603.pdf

I'm well aware of the M14s history and none of it substantiates your claim that it is cop-out cheapo rifle.

[semi_problomatic]

Ok....

It was an extremely budget minded designed rifle (cheap) that used existing designs instead of meeting the needs of the military (cop-out). Hence why it was so quickly replaced.