Nighthawk Custom Firing Pin Stop Flat Bottom Stainless Fully Machined. Designed for a .45 ACP caliber 1911 and Fully Machined from a solid steel billet this firing pin stop is designed to withstand the rigors of competition shooting or everyday carry. Some gunsmithing may be required The Nighthawk Custom line of Fully Machined parts are designed to be the gold standard in the 1911 parts industry. All Fully Machined parts have been fully CNC machined from solid steel billets. We never use cast metal injected moldings or polymer parts. In order to create the Worlds Finest 1911s only the best materials can be used. That is why you can trust Nighthawk Custom Fully Machined parts in your 1911. Specifications for Nighthawk Custom 1911 Firing Pin w/Flat Bottom: Manufacturer: Nighthawk Custom Gun Model: 1911 Caliber: .45 ACP Package Contents: Nighthawk Custom 1911 Firing Pin w/Flat Bottom What firearm models does the manufacturer say Nighthawk Custom 1911 Firing Pin w/Flat Bottom is compatible with? The manufacturer suggests that Nighthawk Custom 1911 Firing Pin w/Flat Bottom is compatible with 1911Nighthawk Custom SP0094: Firing Pin Stop Flat Bottom Stainless Fully Machined