A firing pin assembly is provided that includes a firing pin and a firing pin shaft. The firing pin is received in a slot of the end of the firing pin shaft to be retained therein with a spring retaining sleeve, a main spring, and a mainspring sleeve. The firing pin is removable from the firing pin assembly and can be replaced to result in a prolonged use of the firing pin assembly. The firing pin assembly will operate as a one-piece unit when the spring retaining sleeve is oriented to hold the components securely in place.