A semi-automatic firearm has forward and rearward ends. A receiver has a safety selector aperture, a barrel, a reciprocating loading mechanism and a magazine. A trigger finger and inner portions. The inner portion has a seat with a groove. A disconnector has a hammer hook coupled to the trigger. A trigger mounting pin couples the trigger to the firearm. A trigger disconnector spring couples the trigger and the disconnector. A hammer having an upper striking portion with a disconnector hook receptacle. A hammer mounting pin couples the hammer to the firearm. A hammer spring is coupled to the hammer and hammer mounting pin. A cam body subassembly comprises a cam body housing, a cam and a cam mounting pin. The cam body subassembly is coupled to the firearm. A safety selector is coupled to the firearm. A trigger extender is mated with the upward trigger groove.