CMMG Barrel and BCG Kit 4140CM SBN Drop in Barrel 5.7 x 28mm 5″ Barrel Black
$424.00
2 in stock
The 5” 5.7x28mm Barrel and BCG Kit allows you to build an AR 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. CMMG’s 5.7x28mm Barrel and Bolt Kits are designed to be assembled into a mil-spec AR15 Upper and work with either a CMMG Mk57 lower receiver or with a standard Mk4/AR-15 lower receiver (when using CMMG 5.7 AR Conversion Magazines).
| Upc | 810097502390 |
|---|---|
| Manufacturer | CMMG |
| Manufacturer part number | 57DBC33 |
| Barrel length | 5" |
| Length | 5" |
| Product type | Barrel |
| Shipping weight | 1.485 |
BJ Firearms LLC is a federally licensed firearms business focused on providing quality firearms, accessories, and related services while promoting responsible ownership, education, and community engagement.
The company was founded to serve firearm enthusiasts with knowledgeable service, real-world experience, and a commitment to professionalism and safety.
We focus on real experience, personalized service, hands-on product knowledge, and community involvement — not just sales. Our goal is to help customers make informed decisions and feel confident with their equipment.
Yes. We operate as a federally licensed firearms dealer (FFL), following all applicable federal, state, and local regulations.
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We work with everyone — from first-time buyers to experienced enthusiasts. Education and guidance are a big part of what we do.
We offer firearms, accessories, gear, and related equipment depending on availability and customer needs.
Yes. We help customers evaluate their needs, experience level, and intended use to find the right fit.
Yes. Depending on the request, we can help source specific products or assist with custom configurations.
Yes. We actively engage in hands-on experiences, demonstrations, and community-related firearm activities when possible.
Yes. We support content that helps people learn about equipment, safety, and responsible firearm ownership.
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