Wilson Combat Bullet Proof 9mm AR Firing Pin S-7 Tool Steel. The Bullet Proof Firing Pin eliminates problems that can potentially cause damage to your firing pin and is often the cause of a jammed or inoperable firing pin. The Bullet Proof Firing Pin is CNC machined from a solid steel billet and heat treated to withstand a lifetime of firing and resists mushrooming and cracking. This part is great for those who want a more solid anchor of their firing pin to the firing pin of their Rifle Scope. Package Contents: Wilson Combat Bullet Proof Firing Pin Wilson Combat TR-AR9FP: Bullet Proof 9mm AR Firing Pin S-7 Tool Steel