A compounding dispensing gun includes a pawl-spring assembly and a hand-housing assembly. The hand-housing assembly is coupled to the pawl-spring assembly. The hand-housing assembly has a handle. A plunger assembly extends through the hand-housing assembly and includes a push rod and a push rod head removably coupled to the push rod. The push rod has a plurality of first notches and a plurality of second notches formed thereon. The push rod selectively cooperates with the pawl-spring assembly to advance the push rod and the push rod head during a dispensing operation.