CMMG A1 Receiver Extension Rifle-Length Black Buffer Tube

Description

The CMMG A1 Receiver Extension is a rifle-length buffer tube built for the folks who want that traditional, fixed-stock AR look and feel. It's machined from aluminum and finished in a black hardcoat anodizing that shrugs off wear and holds up to real use. If you've ever handled a classic M16A2 or a retro rifle-length build, this is the tube that makes that setup possible.

What the CMMG A1 Receiver Extension Actually Does

Rifle-length tubes like this one are the longest of the bunch, and they're designed specifically for fixed A1 and A2 style stocks. Unlike a carbine tube, there are no adjustment notches here, which means you're committing to a set length of pull with a solid, rock-steady stock. That extra internal length houses a longer rifle buffer and spring, and the added mass and travel distance give you a noticeably smoother recoil impulse. It's a big reason scoped and precision-minded builds still lean on the fixed rifle-length setup.

Fitment and Build Compatibility

This tube follows the AR-15/M4/M16/LR-308 pattern, so it plays nice across a wide range of builds. CMMG designs it to accept fixed rifle-length stocks and lists it as compatible with Mk4 (AR-15) and Mk3 (LR-308) lower receivers. Keep in mind this is the receiver extension by itself, so you'll want to pair it with a rifle-length buffer, the matching recoil spring, and your stock of choice to complete the assembly. A carbine stock won't work on a rifle-length tube, so plan your parts around the fixed-stock route.

Why Builders Reach for the CMMG A1 Tube

CMMG has a solid reputation for clean machining and dependable parts, and this receiver extension fits right in with that. It's a no-nonsense component that gives your build a strong foundation without any extra frills. For anyone chasing that timeless rifle-length profile or restoring a retro-style AR, this one gets the job done and looks right doing it.