CMMG 9mm Barrel and BCG Kit, 8″ 4140CM, SBN, *Free Shipping*


In stock

$374.95 $359.95

In stock

8″ Medium Taper
1:10 Twist
4140 Chrome Moly
Salt Bath Nitride Finish inside and out
9×19 NATO Chamber
Threaded 1/2-28
Radial Delayed Blowback Bolt (Patent Pending)
Requires enlarged ejection port for reliable operation.
Weight: 1.7lbs

Our MkG GUARD Barrel and BCG Kit allow you to build a Pistol Caliber Carbine using our Patent Pending Radial Delayed Blowback System. Unlike typical direct blowback systems, our RDB uses a bolt that is forced to rotate and unlock, slowing the BCG. This results in a lighter BCG for a lighter rifle, and less felt recoil than a straight blowback system.

Our MkG Barrel and Bolt Kits are designed to work with our MkG Lowers, and a mil-spec upper receiver with enlarged ejection port. Other manufacturers’ receivers may work, but we cannot guarantee function or reliability. For more information regarding fitment, check with our Tech Support team.


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