Colt 9mm Sub Machine Gun Firing Pin. Our Firing Pins are precision machined using our CNC Swiss turning centers. The firing pins are made from domestic 17-4 Stainless Steel then heat treated to an H900 condition. We machine the firing pins from SS to help eliminate internal corrosion issues and improve reliability. The heat treated condition helps maximize the life of the firing pin by increases in Strength and Toughness.