American Built Arms Company Pro 5.56mm Firing Pin Silver Small. Made from AISI 8740 steel and chrome plated. Specifications for American Built Arms Company Pro 5.56mm Firing Pin: Manufacturer: American Built Arms Company Color: Silver Gun Model: AR-15 Package Contents: American Built Arms Company Pro 5.56mm Firing Pin What firearm models does the manufacturer say American Built Arms Company Pro 5.56mm Firing Pin is compatible with? The manufacturer says that American Built Arms Company Pro 5.56mm Firing Pin is compatible with AR-15American Built Arms Company ABAMSFP: Pro 5.56mm Firing Pin Silver Small