The KIDD bolt comes complete with pinned aftermarket firing pin and extractor. Proper headspace allows the bullet to feed properly, and the correct firing pin protrusion guarantees that there is not too much or too little firing pin contact with the rim of the case. This bolt is a flawless match for any KIDD .22LR receiver without modification. You can also use it to upgrade a factory 10/22 style receiver. FEATURES: Aftermarket KIDD .22lr bolt to drop into a 10/22 style receiver CNC Machined steel from billet Proper head spacing and firing pin protrusion Hardened for durability pinned"" firing pin for consistent ignition Radiused and po Mfg: Kidd Innovative Design