Heckler & Koch HK91 & HKG3 Firing Pin, This is a New Firing Pin. Our HK91 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 HK91 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. Firing Pin Length is 4.480 inches with a Nose Diameter of 0.078. Made in the USA!!