Made with 8620 AISI steel and boasting a NIB finish, the Stern Defense bolt fits into Mil-Spec and Glock-pattern upper receivers. It functions with Colt SMG, Glock magazines and it's fully compatible with standard AR15/M16 charging handles. Comes fully assembled with all sub-components installed, including firing pin/spring/retaining pin, extractor, and extractor spring. Also included in bolt assembly is a propriety center and roll pins. Stern's 9mm bolts incorporate a new bolt design which caters to single stage triggers with short resets. It also allows use with the JP silent capture spring. This bolt is compatible with the Law Tactical folding stock and the Echo trigger. Made in the USA Constructed from 8620 AISI steel Custom 4140 billet extractor providing superior ejection Weight - 15.5 oz with, weight 13.3 oz without Compatible with single stage short reset triggers Compatible with the law folding tactical stock Compatible with the Echo trigger Compatible with the JP silent capture spring