The 16.1" 5.7x28mm Barrel and BCG Kit is perfect for building an AR pistol or SBR in 5.7x28mm using CMMG's patented Radial Delayed Blowback operating system. Unlike typical direct blowback systems, Radial Delayed Blowback not only reduces the weight in your BCG but it results in less felt recoil than a straight blowback system and still provides essential features like last round bolt hold open. CMMG's 5.7x28mm Barrel and Bolt Kits are designed to be assembled into a Mk4/mil-spec AR15 upper and work with either a CMMG Mk57 lower receiver or Mk4/AR15 mil-spec lower receiver (when using CMMG 5.7 AR Conversion Magazines).
- 16.1 5.7x28mm Barrel"
- 5.7x28mm Bolt Carrier Group
- Black
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Some firearms, magazines, and accessories are restricted or prohibited in certain states, cities, and counties, and these laws change often. Each order is manually reviewed against the current laws for your shipping address before it ships. If we can't lawfully ship this item to your location, we'll contact you to cancel or adjust your order and issue a refund. You're responsible for knowing and following the laws where you live — if you're unsure, please check or ask us before ordering.