Lightweight small craft gun system

A light-weight, rapid-fire gun utilizing fire-out-of-battery and straight through ammunition feed principles for firing expendable breechcase ammunition comprising:

• a frame:
• a slide assembly trunion mounted on said frame, said slide assembly being provided with a pair of opposed feed and ejection slots;
• a receiver assembly disposed within said slide assembly for reciprocating movement along the firing axis between an ammunition feed and breechcase ejection battery position and a forward firing out-of-battery position, said receiver assembly being provided with a central feed and ejection slot;
• a pair of internal fixed hollow shafts disposed within said receiver assembly on axes parallel to and on each side of the firing axis, the forward ends of said shafts being closed;
• a barrel fixed to the forward end of said receiver assembly and reciprocable therewith;
• an indexing clip feed mechanism fixed to said slide assembly adjacent said feed slot for feeding expendable breechcase ammunition into said receiver assembly through said feed slot;
• a breechcase mechanism assembly disposed within said receiver assembly for receiving ammunition from said clip feed mechanism, supporting said ammunition during firing, and subsequently ejecting empty breechcases through said ejection slot in said slide assembly;
• recoil spring means on said slide assembly normally urging said receiver assembly forward toward the out-of-battery position, said recoil spring means comprising:
• a pair of hollow pistons fixed to the rearward end of said slide assembly and disposed within with hollow shafts, and
• a source of pressurized compressible liquid hydraulically connected to the exterior ends of said pistons to constitute a liquid spring;
• releasable means for latching said receiver assambly in the battery position against the urging of said recoil spring means;
• cam means interconnecting said receiver and slide assemblies for releasing said latching means upon injection of ammunition into said breechcase mechanism assembly and for cycling said breechcase mechanism assembly;
• and
• means for firing the ammunition as the forwardly moving receiver assembly nears the maximum out-of-battery position.