Whether you�re looking to build a AR15 for plinking training or small-game hunting this .22 LR RESOLUTE Upper Group fits the bill perfectly. The Mk4 .22 LR upper is designed to work with any standard AR15 lower and our .22 Conversion Magazines. Available in six different Cerakote finishes all CMMG Upper Groups come complete with bolt carrier group and ZEROED accessories including: - ZEROED AR15 Polymer Dust Cover - ZEROED 22LR Ambi Charging Handle - ZEROED Muzzle Brake 5.56mm - Platform: Mk4 - Caliber: .22 LR - Operating System: Traditional Blowback - Barrel Length: 17 - Barrel Twist: 1:16 - Barrel Contour: MT - Barrel Material: 4140CM SBN - Muzzle Device: CMMG ZEROED Muzzle Brake - Muzzle Thread: 1/2 x 28 - Upper Receiver: Billet 6061 T6 Aluminum - Hand Guard: CMMG EML15 M-LOK - Finish: Cerakote Standard - Charging Handle: CMMG ZEROED Ambi - Weight: 4.0 lbs - Length: 25