CMMG Pistol Receiver Extension Kit – Buffer, Spring & Ambi Sling

Description

Wrapping up an AR pistol build and need the back half sorted? This CMMG kit takes care of your receiver extension group in one shot. It comes with a pistol-specific buffer tube machined from aluminum with a matte black finish, plus the carbine buffer, action spring, castle nut, and an ambidextrous sling mount end plate. Pair it with the lower parts kit of your choice and your pistol lower group is ready to go together.

The standout here is that the buffer tube was designed from the ground up for pistol builds rather than a carbine tube pressed into service. It plays nicely with both .300 AAC Blackout and 5.56 NATO pistol setups, which covers most of what folks are running on a short AR platform. The included carbine buffer and spring keep the action cycling the way it should, so you are not left guessing on spring rates or hunting for parts to make things work.

What the CMMG Receiver Extension Kit brings to the table

The ambi sling mount end plate is a nice touch and one of the reasons this kit earns its keep. It gives you a clean attachment point for a single-point sling and lets you set it up for a left or right side pull without swapping hardware. If you have ever fought a sling that only wanted to hang off one side, you will appreciate having the choice built right in.

A quick note before you tighten things down

One thing worth flagging: the pistol buffer tube runs a slightly larger diameter than a standard mil-spec tube. Because of that, a thicker castle nut wrench may not slide into the gap between the tube shoulder and the castle nut. A slimmer armorer's wrench solves it, so it is good to have the right tool on the bench before you start. Beyond that, this is a straightforward, well-machined kit from a name that AR builders trust to get the details right.