CMMG Barrel and BCG Kit 4140CM SBN Drop in Barrel 5.7 x 28mm 8″ Barrel Black
$398.76
CMMG’s 8″ 5.7x28mm barrel and BCG kit is perfect for building an AR pistol or SBR with Radial Delayed Blowback for reduced recoil and weight.
2 in stock
The 8" 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).
| Weight | 1.775 lbs |
|---|---|
| Dimensions | 17.500 × 1.850 × 1.850 in |
| Manufacturer | Cmmg Inc. |
| Caliber | 5.7x28mm |
| Barrel Length | 8″ |
| Finish | Black |
PROCESSING & SHIPPING
Orders typically ship within 1–3 business days (Monday–Friday) after payment and all required documentation are received. Time to arrival after shipment depends on the carrier. Shipping method is at BT Gun Company’s discretion; ammunition and oversized accessories are charged at actual shipping cost. We do not ship to Hawaii or Alaska.
FIREARM TRANSFERS
- Firearms must ship to a licensed FFL dealer of your choosing — confirm with them first that they can accept the transfer.
- Your receiving FFL will need to email their license to [email protected] before we can ship.
- Inspect your firearm at your FFL’s location before signing ATF Form 4473 — once signed, the firearm is considered accepted.
You’re responsible for knowing the firearms laws in your state before ordering. For complete shipping, returns, and restocking-fee policy details, see our Shipping & Returns page.
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