Mechanism structure for firearms

A firearm apparatus comprising:

• a barrel structure;
• a mechanism head positioned at a back of said barrel structure, said mechanism head comprising:
• a firing pin housing positioned at an end of said barrel structure;
• a firing pin positioned in said firing pin housing;
• a tether pin housing positioned on said firing pin housing;
• a tether pin positioned in said tether pin housing, said tether pin cooperative with said firing pin;
• an extractor housing positioned so as to face said barrel structure;
• an extractor positioned in a space of said extractor housing;
• a lock protrusion having a protruding structure facing toward said barrel structure, the protruding structure having a triangular shape;
• and
• a mechanism rail having a lock housing on a lower surface thereof, the protruding structure fitting into the lock housing;
• a tether bearing positioned on a bearing cutout of said firing pin;
• a pin spring having a thin end facing forwardly and outwardly of a firing pin cavity of said firing pin;
• a cartridge holding protrusion holding a cartridge base, said cartridge holding protrusion positioned in said extractor housing;
• a barrel crown having said barrel structure positioned thereunder, said barrel crown having a push tube and a recoil spring tube positioned thereon, said barrel crown positioned immediately in front of a magazine disc so that said barrel crown resides immediately rearwardly of said barrel structure, the push tube being positioned on an upper portion of said barrel structure such that a back end of the push tube is received in said barrel crown, the push tube comprising a cocking handle protrusion stopping a cocking handle segment at an end portion facing an end of said barrel structure, said push tube further comprising a cocking handle housing having a cocking handle therein, the cocking handle positioned on a side surface of the cocking handle protrusion so as to enable said mechanism head to slide backwardly by transmitting movement obtained from a gas piston in a gas chamber to recoil the spring tube;
• and
• a tube lid positioned in a front end of the push tube, said tube lid being mounted to the push tube by a push tube pin positioned in a pin cavity at an end entering the push tube so as to transmit movement obtained from the gas piston to the push tube, wherein the gas chamber is positioned on said barrel structure so as to be in front of said tube lid, the gas chamber receiving gas resulting from firing such that the received gas causes the gas piston to initiate movement, the gas chamber having a gas hole therein, the gas hole adapted to release the gas from said barrel structure, the gas chamber having discharge holes adapted to discharge excess gas and particles from the gas chamber.