Abstract: In an automatic weapon system such as the AR-15/M-16, the passage of propellant gas-carried heat, powder residues, and dirt to the bolt carrier and the upper receiver of the weapon is eliminated. The standard recoil spring housed in the buttstock of the weapon can be eliminated to produce a weapon with a folding stock or a machine pistol. Propelling gasses drive a piston which in turn drives a piston rod which is integrally coupled with the carrier key of the weapon. There is no relative movement between the rod and the carrier key. Therefore, no impact is delivered by the rod to the carrier. Longer carrier life is assured. The original recoil spring can be eliminated by a recoil spring on the piston rod. The ability to vary the volume of the gas chamber in which the piston is driven permits control of the firing rate of the weapon. A further enhancement permits the total blockage of propellant gasses from the gas cylinder so that the weapon may only be fired in a single action, single shot mode.

Abstract: An improved muzzle brake having a generally upward opening void from which escaping gases create a downwardly directed reaction force and a sloping face on which the propelling gases collide and expand and deflect to either side and upward of the muzzle brake to defeat the natural tendency of the muzzle of a weapon to climb and drift. Below the generally upward opening void, within the floor of the bore of the muzzle is a venturi trough in which a lowered pressure region of propelling gases is created by the high speed passage of the propelling gases down to the bore of the muzzle brake. This lowered pressure region within the venturi trough is still in excess of the environmental pressure exterior of the muzzle brake so that gases within the venturi trough escape through channels directed downwardly and to the left and right of the projectile path.