CMMG 5.7x28mm 8″ Barrel with Bolt Kit – Radial Delayed Blowback AR Conversion Black

The CMMG 5.7x28mm 8-inch Barrel with Bolt Kit is designed to convert compatible AR-platform firearms to the fast, flat-shooting 5.7x28mm cartridge using CMMG’s proven Radial Delayed Blowback (RDB) operating system. This high-performance conversion kit allows builders and enthusiasts to create a compact, lightweight AR pistol or short-barreled rifle chambered in 5.7x28mm while maintaining smooth recoil impulse and reliable cycling.

CMMG’s Radial Delayed Blowback technology reduces recoil and improves system efficiency compared to traditional straight blowback designs. The included bolt carrier group and matched 8-inch barrel are engineered to work together for optimal reliability, making this kit an excellent choice for AR builders looking to assemble a dedicated 5.7x28mm upper receiver.

The 8-inch barrel length provides excellent velocity performance in a compact configuration, making it ideal for range builds, defensive platforms, or compact AR pistol setups. Precision machining and CMMG’s well-known manufacturing standards ensure durability and long-term performance.

Quick Highlights:
• Designed for AR-platform builds chambered in 5.7x28mm
• Includes 8-inch barrel and matched bolt carrier group
• Utilizes CMMG Radial Delayed Blowback (RDB) system
• Improved recoil control compared to traditional blowback systems
• Ideal for compact AR pistol or SBR builds
• Precision manufactured for reliability and durability

Use Cases & Applications:
• Building a dedicated 5.7x28mm AR upper receiver
• Compact AR pistol or SBR builds
• Range shooting and recreational use
• Personal defense AR platform builds
• Custom AR firearm projects

Technical Details:
• Manufacturer: CMMG
• Product Type: Barrel and Bolt Kit
• Platform Compatibility: AR Platform
• Caliber: 5.7x28mm
• Barrel Length: 8 Inches
• Operating System: Radial Delayed Blowback (RDB)
• Finish: Black
• Included Components: Barrel and Bolt Carrier Group