Abstract: A light-weight, shoulder-firable, armor-penetrating gun characterized by a recoiling barrel confined to coaxial movement by a pair of longitudinally spaced bushings within the gun housing, the recoiling barrel being adapted to carry rearward the elongated bolt carrier containing the bolt for compressing the recoil spring, and a stop mechanism associated with the barrel and the housing for limiting the rearward travel of the barrel for early disengagement between the barrel and the bolt carrier, and a barrel spring in the front of the housing for returning the barrel to its normal battery position.

Abstract: A bolt assembly for an automatic firearm which operates using kinetic recoil energy that includes a floating bolt element, a rotatable locking bolt head and a return spring interposed between them, all in communication with the barrel. The bolt head is formed with a cylindrical portion having two crescent shaped projections located at diametrically opposite points along the circumference of the cylindrical portion. The barrel is formed with two diametrically opposite recesses associated with and shaped to correspond to the projections. The barrel is also formed with a pair of grooves, each groove associated with a recess such that the projections may enter and exit the grooves through the recesses. The grooves are staggered with respect to the recesses and have an angular extension such that the projections may enter and be retained within the grooves.