This is your firing pin stop if you have a 9×19 caliber 1911, expecially those with Gov't Model slides. The Extreme service firing pin stop is CNC machined out of an oil-quenching tool steel that was chosen for a balance of impact and wear resistance. GI hardness is 44-50 and Harrison Design shoots for 46-48 Rc. The Extreme Service FPS is made .480"" wide so it can be fitted to your slide and extractor to prevent extractor ""clocking"". It has a chamfered fitting pads on each side to make your job easier and the FPS fit better in to the slide. It has a maximum sized radius machined on the bottom rear corner to make it easier for the 9mm cartridge Mfg: Harrison Design & Consulting
