How to design gas system?

[barnbwt]

"So what you are saying is a rifle that only fires a single shot with one pull of the trigger used a electric motor to extract, eject, feed, and chamber the next cartridge BATF would consider that a full auto?"

I don't think they've stated this clearly, but any firearm that can load its own ammo into the chamber with a purely electronic trigger/ignition actuation can be made full auto as easily as any "smart gun" can be overridden (in either direction). You simply pulse the electronic signal at a frequency slower than the gun cycles, and it will continue to fire. If that pulse can be generated by anything other than a finger (and obviously it can) the ATF will rule the design as readily convertible to full auto.

The solution, at least while the NFA persists, is to make a hybrid trigger, where electrical parts work in conjunction with positive mechanical resets. While more complicated, a mechanical trigger assisted by electrical solenoids could achieve many of the supposed benefits of electrical activation (apart from simplicity). I believe there's a design more or less to this effect making its way through the TB determination process as we speak, though the name escapes me.

Nom,
I was thinking of recoil operated MGs around the turn of the century, but you're right that large, mounted/wheeled guns were developed concurrently with gas operated. Recoil seemed to rule the day up into the 30's/40's, though (recoil w/ gas boost, to be specific). Probably had more to do with corrosive ammo than anything, to be honest. I personally don't count Browning's lever-gun-with-a-spoon-and-bailing-wire an invention, per se, or at least not a complete one (his Potato Digger Colt was, though). I don't know as much about the Maxim Gun's development as I should, but I know that the man found recoil operation to be the most successful for him. My main point was that recoil operation is easier to work to in the absence of decades of development and machine technology, but now that we have those, gas operation is a more efficient solution in the "rifle" portion of the design space.

Here's a cool modern rifle that works on long-recoil; GM6 Lynx in 50BMG (also supposedly in 14.5 Russian)

TCB

 

[Nom de Forum]

Nom,
I was thinking of recoil operated MGs around the turn of the century, but you're right that large, mounted/wheeled guns were developed concurrently with gas operated. Recoil seemed to rule the day up into the 30's/40's, though (recoil w/ gas boost, to be specific). Probably had more to do with corrosive ammo than anything, to be honest. I personally don't count Browning's lever-gun-with-a-spoon-and-bailing-wire an invention, per se, or at least not a complete one (his Potato Digger Colt was, though). I don't know as much about the Maxim Gun's development as I should, but I know that the man found recoil operation to be the most successful for him. My main point was that recoil operation is easier to work to in the absence of decades of development and machine technology, but now that we have those, gas operation is a more efficient solution in the "rifle" portion of the design space.

Here's a cool modern rifle that works on long-recoil; GM6 Lynx in 50BMG (also supposedly in 14.5 Russian)

TCB

What I was referring to is that Maxim is credited for the principle of gas operation but Browning was the first to use it successfully. Maxim wisely decide to concentrate of recoil operation because he did after all begin with black powder cartridges being used in his MG. Maxim is also credited with several other things Browning used: adjustable headspace, the recoil accelerator, and T-slot extractor. Browning’s first machinegun was not the modified lever action rifle. He created an a gas operated machinegun that while impractical was a true machinegun. The gas operated 1895 “Potato Digger” followed this first design.

 

[briansmithwins]

I suspect recoil operation was better suited to the steel alloys* that were available, and weren't as adversely effected by the corrosive primers that were common until after WWII.

BSW

*And lack of consistent heat treating.

 

[Bezoar]

theres alot to it. a lot.
just look at the pmr 22 mag from keltec. lots of interesting ideas from that, but they created a one off design that will be impossible to size up for say a 9mm or 357 sig.

 

[MachIVshooter]

just look at the pmr 22 mag from keltec. lots of interesting ideas from that, but they created a one off design that will be impossible to size up for say a 9mm or 357 sig.

Certainly not impossible, but definitely impractical. .22 WMR has some unique internal ballistics that make it a challenge in autoloader, and especially handguns. Various delayed blowback systems and a few gas systems have been employed with a host of handgun rounds, but conventional service pistol cartridges are best suited to a conventional short recoil design, be it a Browning style titling barrel, Walther/Beretta type locking block, Pedersen type camming breech block or other.

 

[briansmithwins]

The Browning short recoil design works so well in pistols because it's cheap to make, compact, and strong enough for typical pistol cartridges.

When you get to shoulder weapons, simple blowback is king because a 2lb bolt isn't that much of a issue when mated to a longer barrel and stock. Plus, blowback is about as simple (and cheap) a firearm action as can be designed. No locks, tilting parts, rotating bits, or gas system required.

BSW