Springfield Armory was involved in experimenting with he M1 Garand throughout its production, looking at various different elements that could be improved. A series of experimental models were made, with M1E[x] designations. Some of these went on to become production models like the M1C and M1D snipers, while others simply proved that some idea were not feasible. One of these failed experimental models was the M1E10, made in 1944.
The M1 Garand was a rather complex gun to manufacture, and Springfield was aways interested in ways to simplify it. The operating rod in particular was a tricky part to make, with its slight but very high-tolerance bend. After acquiring an AG42 Ljungman rifle from Sweden, Springfield decided to try adapting the Ljungman gas system to the M1. By using a gas tube to redirect gas back about 6 inches before venting onto the gas piston, the hope was to eliminate the bent section of operating rod. Instead though, testing concluded that the venting hot gasses caused more problems inside the stock than the manufacturing improvements would have justified.
Thanks to the Springfield Armory National Historic Site for giving me access to this truly unique specimen from their reference collection to film for you! Don’t miss the chance to visit the museum there if you have a day free in Springfield, Massachusetts:
https://www.nps.gov/spar/index.htm
It’s more a shortened op-rod M1 than a direct impingment M1, just to say of how the two systems are really not clearly defined.
It only needed to drill a pair of holes in the cup, so that, after the bolt recoiled enough, the gas was expelled externally, to solve the problem. The ljugman patent already anticipated it. But there would stll be the problem that soldiers can’t put their hands there.
It’s hard to figure out why they didn’t simply shorten the op-rod and put the cup/cylinder on it, barely protruding from the end of the stock, where there wouldn’t have been any gas-related problem.
“barely protruding from the end of the stock”
Would this have been susceptible to getting fouled with a dogface did a plant into the dirt to avoid being hit?
It would be closed, bar for the moment the rifle fires. It’s exactly the same setup than the Degtyaryov machine gun, that was quite rugged,
However, to me, the original op rod is still there not for a question of weight, but because the cylinder contains the recoil spring.
In a future production, it could have been shortened (that of the M1 Garand is fairly long for what it does) but, for the prototype, they wanted to work with original components (also because, the less you change, the more you know what’s wrong if the rifle doesn’t work).
“(…)After acquiring an AG42 Ljungman rifle from Sweden, Springfield decided to try adapting the Ljungman gas system to the M1.(…)”
Now this raises question if M1E10 does infringe U.S. patent of Ljungman? If so were 1940s U.S. decision-makers for infantry weapon willing to pay for foreigners patents to use protected solutions?
Ljungman patented his system in the US only in 1943, maybe exactly because he overheard of those experiments.
However is debatable if the patent was even valid. The French, IE, didn’t pay anything to Ljungmann, since they were toying with the same solution since the early ‘900. And, in this case, the op rod is only shortened, not eliminated,The cylinder is still external to the bolt carrier.
I imagine that Eugene Stoner was at least aware of these developments, and they fed into his AR-10 design.
The interesting thing about the AR-10 basic design is that it’s not actually “direct impingement”, and yet it also uses the gas elegantly while disposing of it to the side, which accomplishes a bit of cooling effect and simultaneously blows filth and funk out with it.
Which is something I never appreciated much, until late in my military career when I got my hands on some high-speed camera footage and observed what was really going on with the mechanism. It’s not what people have wrongly assumed for decades, now.
So, strictly speaking, when the original M16 was sold as a ‘self-cleaning” rifle, it pretty much was. That is, assuming you used ammunition loaded with something other than ball powder.
As for the operating rod issue, it seems to work well enough on the M1/M2 carbine, even in full-auto fire on the latter. I suspect the OAL of the cartridge and the dependent “stroke” of the rod might have something to do with that. Perhaps a cartridge with a 2.24 in case length and a 3.34 in maximum allowable OAL is just a bit too long for that kind of mechanism.
It seems to be iffy with 7.62 x 51mm as well, but apparently is “happy” with 5.56 x 45mm, 7.62 x 39mm, or 7.62 x 33mm. It’s worth noting that even Bill Ruger and his designers had trouble “scaling up” the Mini-14 to produce a 7.62 NATO rifle similar to M14 or BM59.
https://i0.wp.com/laststandonzombieisland.com/wp-content/uploads/2015/03/9.jpg?ssl=1
So maybe the problem is too long cartridge + too long operating rod + excessive flexure = oops.
Limiting this kind of action to cartridge OALs under 6.5 cm might be the answer.
clear ether
eon
The Garand op rod design has always struck me as crazy; why would you do it that way, and have all the force lines go off-center?
It would have been easier to do the design with two legs, one on either side of the bolt. Some of the European semi-autos did it that way, and that just strikes me as being a lot more sensible; even things up.
If the mechanism was like the AK, with the gas piston and op rod centered, no problem. But, when you have the whole thing off on the side, then the recoil energy is going to tend to abuse the mechanism badly.
Frankly, this is one of the main reasons I never warmed up to the Garand, the M14, or the Mini-14.
Not to mention the whole finger-trapping issue. Which I admit is what I see as the one major drawback of my old friend the M1/M2 Carbine.
Fortunately, on it the worst that generally happens is a stoppage. A properly-designed upper handguard (stamped steel and ventilated, if you please) eliminates even that in addition to reducing heat buildup in full-auto fire on the M2. (That composite handguard on the M14 was supposed to do the same thing; in fact it made it worse.)
Ruger took the hint on the Mini-14 after 1990, with a synthetic handguard that covers the operating rod. Which give the rifle a curiously “unbalanced” look and balance.
Exactly where to hide the op-rod on any gas-operated arm has always been one of those things. As you say, twin rods, probably round rather than squared cross-section, tucked in either side of the bolt underneath as on most gas-operated shotguns (Remington 1100) are the best layout. And there, they can easily be routed around the feed system.
The Garand operating rod may have become current in American design simply because anything else upset Ordnance. And that tended to get you “cancelled”.
clear ether
eon
You have to wonder at just how much bad design was driven by “Ordnance doesn’t like that”. We know the Germans had a mania against tapping gas off the barrel, and preferred gas-trap at the muzzle, which arguably set a lot of their designs back.
I like the simplicity and redundancy of the AR-18 recoil springs/bolt carrier setup. If I were doing it, I would have the springs on captive rods that locked in firmly on the front of the receiver and in back, with the carrier riding on the rods. You wouldn’t need rails in the receiver or even tracks; you could get by with simple sheet metal or extrusions for your receiver, and rely on the bolt/barrel extension for your precision locking, with everything else being pretty high-tolerance and low precision. I think that even the AR-18 is a little much for manufacture, looking at how Royal Ordnance screwed the pooch on the whole SA-80 redesign from the original.
Ideally, the weapon you design should work regardless of quality of manufacture; in fact, the higher precision and worksmanship required to make your weapon work, the worse a job you’ve done.
Ideally, you’re able to do like they did with the STEN, and have a hundred small factories churning out components that combine into something workable…
@ Kirk
That’s how the Tavor works IE, even if there they deceided to separate the “bolt carrier guiding rods” function form the “recoil spring rod” function, with the recoil spring benig placed higher, in a pure AK47 fashion.
Since the M1 Garand requires the op-rod to ride over the magazine and on the side of the bolt, the “natural” setup would have been to have the gas piston over the barrel. The op-rod would have been a straight pipe, containing also the recoil spring, like in the original, but with a “U” shaped last part to operate the bolt, that could have been easily obtained bending a straight bar.
It had not been made like that only because, in the ’20s and ’30s, a low-barrel setup “didn’t seem right”.
Not to say that, this way, gas port, cylinder, piston, op-rod, and recoil spring would have been easily accessible simply removing the upper handguard, and the bolt/carrier could have been made field-strippable (see the Breda PG, IE), while the M1 Garand was easily disassemblable, but not really field-strippable (you have to take the entire rifle apart to access the firing pin, IE).
The Garand basically copied the layout of the French RSC 1917. Twin, balanced op-rods only help a design that utilizes a bolt carrier. The M1, M1 Carbine, M14, Mini-14 family are rotated directly by the op-rod.
I wonder what would have happened if someone had thought to take the Remington 8 bolt w/bolt carrier and receiver setup and married it to an under-barrel gas system with twin rods. This isn’t that big of a stretch in the 1920’s, a full generation before Kalashnikov did the same thing but with the gas system over the barrel.
Kirk,
Other than the “captive” part, that is how the AR18 works. The upper is just thin sheet metal. It’s clear in Ian’s (Nov 19) video. Royal Ordnance just showed great diligence in finding other opportunities to screw up
I agree completely with the view of design you described. A popular naval quote is that “an expert shiphandler is one whose expert judgment keeps him out of situations requiring expert shiphandling”. By the same token, with a few exceptions, an expert design is one that minimizes dependency on expert craftsmanship.
“(…)seems to work well enough on the M1/M2 carbine, even in full-auto fire on the latter. I suspect the OAL of the cartridge and the dependent “stroke” of the rod might have something to do with that. Perhaps a cartridge with a 2.24 in case length and a 3.34 in maximum allowable OAL is just a bit too long for that kind of mechanism.(…)”
Carbine Williams developed self-loading rifle for longer cartridge, it is now known as Winchester-Williams anti-tank rifle https://guns.fandom.com/wiki/Winchester-Williams_anti-tank_rifle it does consume 12,7×99 cartridge. Testers ranked it high. It was never put into mass production due as U.S. forces not perceiving need for such weapon at that time.