[Dr.Zoidberg]

PS The government answer to the printable gun will be to remove ammunition from the civilian market. Casting lead bullets is no problem. Making cartridge cases without a deep draw press, not so easy. Making smokeless powder and primers (or even percussion caps), big problem. Go back to flintlocks, I don't think so...BLOAT

Ammunition and propellent are a dangerous bottleneck in open source arms, as a new direction of thought, I suggest looking to the gas propelled paint marker (or paintball) guns and the modern air rifles used for taking big game for inspiration.

http://www.quackenbushairguns.com/

If one is serious about creating an arm that resists being rendered useless simply through stopping ammo production, then a compressed gas powered projectile weapon is a reasonable direction to consider. The potential for a true everyman's arm might lie here.

[Jed Eckert]

Lewis and Clark carried an air rifle on their expedition. The rifle was way ahead of its time.

Girandoni Air Rifle

[Spktyr]

There are also people working on hand-held Gauss weapons. There’s a guy in Russia that has a pistol that fires a steel pinball magnetically at 300 feet per second and can fire once every 30 seconds. This is only improving as controllers and capacitors get better - and there’s no propellant. Ammunition is anything steel that will fit in the bore.

[Gandalf_The_Gray]

If one is serious about creating an arm that resists being rendered useless simply through stopping ammo production, then a compressed gas powered projectile weapon is a reasonable direction to consider. The potential for a true everyman's arm might lie here.

An excellent suggestion if the ultimate aim for the weapon is meat for the pot or maybe some intermediate range sniping. I'm afraid that the pace of modern warfare demands a rate of fire unsustainable by an externally pressurized gas system.

Let's suppose a rate of one shot per second for thirty seconds. How big must the gas reservoir be to maintain that rate while maintaining a pressure high enough so as not to affect point of aim? How long would it take to restore the reservoir to full pressure with a hand pump?

A reasonable answer to these questions will define a practical combat weapon. If, however, the reservoir is the size of a brace of scuba tanks and takes and hour to recharge I would question its utility.

A spring/piston design is essentially a single shot and would suffice for hunting. A design of either type that minimizes muzzle report and was reasonably compact would be useful to eliminate pests without waking up the neighbors.

Regards,
GtG