When it comes to dimensions and the caliber this is what comes to most people's minds when you say AR15. This CMMG RESOLUTE comes chambered in 5.56x45mm one of the most prolific calibers in the world and for good reason. 5.56 and its counterpart .223 Rem have seen service with militaries hunters and recreational shooters for decades. - Whether you're considering your first rifle or picking a new addition a 5.56 RESOLUTE carbine is a staple for any collection. - If you're after a particular look or have a certain AR accessory that fits you best then don't worry this 5.56 RESOLUTE is built on our Mk4 platform and accepts virtually any and all AR15 accessories. - When full-size rifles are too cumbersome and pistols/SBRs don't deliver the long-range ballistic performance you need the CMMG RESOLUTE line of carbine length rifles is the answer. Fitted with the suite of ZEROED parts and accessories as well as our legendary RIPSTOCK the RESOLUTE is the rifle that's never out of place. The new EML 15 handguard brings style to the next level. M-LOK attachment slots are found where expected at the 3 6 and 9 o'clock positions as well as on top at 12 o'clock with the omission of a full-length Picatinny section found on our previous handguard. This reduces weight while the additional M-LOK section still gives shooters a place to mount those must have accessories. With a range of choices just pick the caliber you need for the job and let your rifle do the talking. - Platform: Mk4 - Caliber: 5.56x45mm - Operating System: Direct Impingement - Barrel Length: 16.1 - Barrel Twist: 1:7 - Barrel Contour: MT - Barrel Material: 4140CM SBN - Muzzle Device: CMMG ZEROED Muzzle Brake - Muzzle Thread: 1/2 X 28 - Gas Port Location: Mid - Gas Block: 0.750 Non-Adjustable - Upper Receiver: Billet 6061 T6 Aluminum - Lower Receiver: Mk4 Forged 7075 T6 Aluminum - Hand Guard: CMMG EML15 M-LOK - Finish: Cerakote Standard - Charging Handle: CMMG ZEROED Ambi - Pistol Grip: CMMG ZEROED Pistol Grip - Buffer Type: Carbine - Receiver Extension: CMMG 6 Position Fastback Extension - Stock / Brace: CMMG RipStock - Trigger Type: Mil-Spec Single Stage - Trigger Guard: CMMG ZEROED Trigger Guard - Safety Selector: CMMG ZEROED 60/90 Degree - Magazine: Magpul 30rd PMAG - Weight: 6.4 - Length: 32.5