CMMG's Sierra rimfire uppers feature many significant improvements over previous designs, enhancing functionality, reliability, and ease of use. Prominent among these improvements are an Anti-Jam Charging Handle, Live Round Extraction ability, and Gas Deflector. CMMG's durable Weapons Armament Surface Protection (WASP) Melonite treatment has been applied to the barrel and surface-hardens the steel, extending barrel service life by reducing friction in the bore and lessening bore surface wear.
The Sierra upper is ready to drop on to any standard mil-spec lower receiver, all that's needed are a compatible magazine and a pile of 22 LR ammunition to start enjoying some inexpensive and fun time at the range! Compatible with Black Dog Machine and CMMG rimfire AR-15 magazines (not included). CMMG recommends the use of Plated 40 grain High Velocity 22 LR ammunition for optimal functioning.
- Upper Receiver: A3 Flat-Top w/Ceramic Finish
- Barrel Length: 16"
- Barrel Contour: M4
- Barrel Material: Chrome Moly Steel
- Muzzle Thread Pattern: 1/2"-28
- Chrome Lined: No
- Barrel Finish: WASP Melonite
- Twist Rate: 1 in 16"
- Chamber: 22 Long Rifle
- Muzzle Device: A1 Flash Hider
- Gas System Length: None, Blowback
- Gas Block Diameter: 0.750"
- Handguard: Polymer M4-Style
- Sights: None, Single Rail Gas Block/Front Sight Base
- Extras: Gas Deflector, Anti-Jam Charging Handle, Non-Functional Forward Assist Plug, Live Round Extraction
- Magazine Not Included, Compatible w/Black Dog Machine & CMMG Magazines
Please Note: Installation of AR-15 upper assemblies with certain features including, but not limited to: flash hiders, bayonet lugs, and threaded muzzles may violate state and/or local laws.