Everything you need to convert your existing upper to a dedicated .22LR. Just purchase a magazine and you are ready to go. For best performance use a round style hammer as notched hammers can cause function issues and 36 grain plated nose bullets have proven to be the best choice for function.

Specs
Caliber:.22LR
Barrel Twist: 1×16
Barrel Contour: M4
Barrel Material:4140CM, SBN (salt bath nitride)
Barrel Thread: 1/2×28