The 5.56mm equivalent of a Sten gun...?

[cluttonfred]

What is the cheapest, simplest, easiest to manufacture 5.56mm assault rifle ever made, something in the spirit of the Sten or other "stopgap" weapons? The TRW Low Maintenance Rifle (below and links) is certainly one candidate, but there must have been other attempts to make a really cheap 5.56mm assualt rifle. Any ideas?



http://en.wikipedia.org/wiki/TRW_Low_Maintenance_Rifle
http://world.guns.ru/assault/usa/trw-lmr-e.html
http://www.forgottenweapons.com/rifles/trw-low-maintenance-rifle/

 

[barnbwt]

Probably an AK74 with a different barrel* . I put money on a roller, gas, or lever delay blowback as being the cheapest possible solution, but even that requires forgings only practical on an industrial scale. For a gun suited to today's small but super-capable machining techniques (CNC, EDM, aluminum, etc.) the AR is probably easiest for a small shop to tool up for. Were that the case in the 60's, the weapon would have had as big an impact on the world as the AK47.

*This would be the SIG 55X series rifles, only made with budgets in mind rather than OCD. The Beretta AR70 is closer to that goal, and was probably somewhat cheap if the program was managed competently.

TCB

 

[ECVMatt]

The TRW LMR actually looks like a pretty cool idea to me.

 

[modifiedbrowning]

AR-18?

 

[AK103K]

How about the original "Bushmasters"?

 

[briansmithwins]

My vote would be for the original AR-18 also.

Stamped sheet steel spot welded together with most of the other parts easily made on a screw machine.

And since the bolt carrier ran on the spring rods (similar to the AUG) it's more dirt resistant than many other rifles.

BSW

 

[Nom de Forum]

How about a Kel-Tec?

 

[henschman]

^^ Exactly what I was thinking. This reminds me a lot of the Sten:

 

[BCRider]

The simplicity of the Sten came from the simple and direct blowback method of cycling. With the 5.56 I can't see that being a viable way to go due to the power of the round that would require a very heavy bolt and recoil spring.

This is why all the simple direct blowback semi and full auto guns work with handgun rounds and not rifle rounds. Meanwhile looking at all of the "simple" guns posted so far that use the 5.56 I see that they all use direct gas or gas piston actions for cycling. That pretty much takes the description of "simple" away. Especially when the power of the round requires the bolt to lock in place in some manner.

 

[briansmithwins]

The Brits were making the STEN at a unit cost of about £10 per copy late in the war, but as was mentioned, any assault rifle (defined as full auto firing intermediate cartridges) needs to have some way to slow the bolt opening so the brass doesn't rupture.

Delayed blowback, in theory, gets you there and is easier to manufacture than gas piston operation. In reality, HK never got their unit costs for the G3 or HK33 much below (if at all) that of the competing designs like the FAL or M16 series.

BSW

 

[barnbwt]

"In reality, HK never got their unit costs for the G3 or HK33 much below (if at all) that of the competing designs like the FAL or M16 series."

Even a cursory glance through the design and function of the G3 series shows it is replete with 'great ideas' that may or may not be particularly necessary for function, but certainly contributed enormously to its R&D and production costs. A true simple roller or lever delayed tube gun could be made far simpler

-That ridiculously complex FCG apparatus
-That ridiculously complex tensioned bolt design
-That ridiculously complex and sensitive cocking handle scheme
-The complex mag release scheme is more than what's needed
-Unnecessarily complicated stampings for receiver and magazines

The rest of the gun (stamped tube receiver, cast trunnion, detachable lower, pressed/pinned barrel) is brilliantly simple once tooled up for --and no design will be very economical on a small scale -- and could make for a very simple and functional weapon.

I also suspect a primer-actuated design could be made pretty simply, if based off the Degtyarov locking flap scheme; very simple and easy to make parts, and with no gas system if primer actuated.

TCB

 

[Nom de Forum]

The simplicity of the Sten came from the simple and direct blowback method of cycling. With the 5.56 I can't see that being a viable way to go due to the power of the round that would require a very heavy bolt and recoil spring.

This is why all the simple direct blowback semi and full auto guns work with handgun rounds and not rifle rounds. Meanwhile looking at all of the "simple" guns posted so far that use the 5.56 I see that they all use direct gas or gas piston actions for cycling. That pretty much takes the description of "simple" away. Especially when the power of the round requires the bolt to lock in place in some manner.

Simple is a relative term. What is simple for a 5.56 rifle is complicated for a 9mm blowback system SMG. DI is simpler than any of the other gas systems. Take a look at the DI system on a MAS 49/56, it doesn't get much simpler than that. Much simpler than the M16. Plastic receivers and furniture is simpler than metal. I think getting a Primer Actuated system in a cheap and simple rifle to be reliable may be a challenge. I still think the Kel-Tec comes close to simple as possible without being impractical to use. A simple blowback 5.56 would be impractical for example.

 

[jobu07]

How about the M231 port firing weapon? It's a pretty simplified M16 variant.

 

[cluttonfred]

The Brits were making the STEN at a unit cost of about £10 per copy late in the war, but as was mentioned, any assault rifle (defined as full auto firing intermediate cartridges) needs to have some way to slow the bolt opening so the brass doesn't rupture.

Delayed blowback, in theory, gets you there and is easier to manufacture than gas piston operation. In reality, HK never got their unit costs for the G3 or HK33 much below (if at all) that of the competing designs like the FAL or M16 series.

BSW

Interestingly, I just ran £10 through a historic inflation calculator, and £10 in 1945 is equivalent to about £365 or about US$608 today! So I guess cheap is a very relative term and the Kel-Tec starts to look like a bargain if you can actually find one. Still, like ECVMatt, that TRW LMR does spark my imagination.

 

[Dr.Rob]

Those old Bushmasters sure look like garage folded steel with a few welds and pre-made AR/AK parts. They 'feel' Sten-like.

 

[cluttonfred]

This one is not 5.56mm but actually 7.62 NATO, but it does suggest one way to go. As someone suggested earlier in the thread, it's a delayed blowback design, lever-delayed in this case. Presumably, a stock of some sort was also planned!



More info here http://en.wikipedia.org/wiki/Sterling_7.62 and here http://www.forgottenweapons.com/british-308-sterling-prototype/ and here http://homemadedefense.blogspot.com/2012/03/sterling-762-nato.html.

5.56mm ought to be a lot easier that a full-bore rifle cartridge.

Cheers,

Matthew

 

[briansmithwins]

5.56mm ought to be a lot easier that a full-bore rifle cartridge.

I dunno. Once you're doing rifle class cartridges you're talking about pressures on the order of 50,000 psi, which means you're going to need some kind of locking or delay mechanism since brass won't handle those kind of pressures unsupported.

Sure., you can make a 556 rifle with smaller parts than a 762 one, but both are going to need to be decent steel and have some mass to the operating parts if you want to get any kind of life out of them.

BSW

 

[Jim Watson]

We get it, guys, you cannot make a high velocity rifle as cheaply as a blowback SMG.
But you CAN apply the principles to keep the cost down.
The STEN was made from pressings and simple turnings, with the tolerances generous and well thought out so parts could be made by subcontractors all over the place.

My first thought was the AR18. Stoner realized that the AR15 took a mature aluminum industry to make the aluminum and forge it into big parts like rifle receivers. He designed the AR18 for producers whose capabilities stopped with sheet metal stamping and straightforward machining. Could it stand the subcontracting? I don't know, but the hypothetical Cheapgun should.

The Bushmaster design might work.

Or just make AKs fudged to USGI as has been suggested and done.

 

[briansmithwins]

The Armalite rifle project was intended to leverage aircraft industry production methods, like foam filled composites (think helicopter rotor blades) and forged high strength aluminum.

The AR18 was intended for countries with a less developed industrial base. Basically, if you had a tractor engine factory, they would be perfectly capable of making AR18s.

BSW

 

[Fishbed77]

Saiga rifle in .223.