CMMG Resolute MK4 5.56 AR-15 Barreled Upper Receiver - Black - 16.1" - 55BB40B-AB
In stock
Upgrade your next AR-15 build with the CMMG Resolute MK4 5.56 Barreled Upper Receiver, designed for precision and durability. Featuring a 16.1″ Chrome Moly barrel with a medium contour and a 1:7 twist rate, this upper receiver delivers superior accuracy and handling. The 1/2×28 threaded muzzle is equipped with the CMMG ZEROED muzzle brake, helping reduce recoil and improving follow-up shots.
The barrel, made from 4140 chrome moly steel, is coated with a salt bath nitride finish for corrosion resistance and longevity. The mid-length gas system ensures smoother operation and recoil management, making it a reliable choice for any shooting scenario.
The upper is machined from billet 6061-T6 aluminum with a durable black Cerakote finish, paired with the CMMG EML15 M-LOK handguard for added customization options. With a total weight of just 3.6 lbs and an overall length of 25 inches, this upper receiver provides excellent balance and maneuverability.
Features:
- MK4 platform
- 5.56 NATO
- Direct impingement
- 16.1″ barrel length, MT contour
- 1:7 barrel twist
- 4140 CM barrel material, salt bath nitride finish
- CMMG ZEROED muzzle brake
- 1/2×28 muzzle thread
- Mid-Length gas system
- Billet 6061-T6 aluminum upper receiver
- CMMG EML15 M-LOK handguard
- Black Cerakote finish
- Weight: 3.6 lbs
- Overall length: 25″
| Weight | 60.8 oz |
|---|---|
| Dimensions | 31.3 × 4.9 × 3.3 in |
| Barrel Finish | Nitride / Melonite |
| Barrel Profile | Medium |
| Cartridge Compatibility | 5.56 NATO |
| Barrel Length | 16" |
| Gas System Length | Midlength |
| Twist Rate | 1-7 |
| BCG / Charging Handle | Not Included |
| MPN | 55BB40B-AB |
| UPC | 810103473461 |
Compliance
NFA (National Firearms Act) compliance is crucial for legal ownership and transfer of regulated firearms and accessories like short-barreled rifles, suppressors, and certain types of ammunition, ensuring adherence to federal regulations to avoid legal penalties and ensure responsible firearm ownership.
