Adjustable Carbine Stock & Buffer Tube Assembly

Whether you bought stripped lower, or just finished an 80% lower, you’ll need two components to assemble it and make it functional: A lower parts kit, and a buffer tube assembly like this one. Buffer tube assemblies work with your lower parts kit, allowing your lower and upper receivers to work together.

What’s Included

• Buffer Tube
• Carbine Buffer
• Recoil Spring
• Castle Nut
• Latch Plate
• Buttstock

Mil-Spec / Standard Buffer Fitment

This buffer assembly includes a mil-spec tube with an outer diameter of 1.148″ and a thread pattern of 1-13/16″ x 16. It’s designed to fit any typical AR-15 stripped lower receiver or 80% lower that’s also advertised with mil-spec fittings. Virtually all modern AR-15 receivers are manufactured with mil-spec fittings.

Commercial vs. Mil-spec Buffer Tubes

This buffer tube is also machined with the appropriate detents necessary for any adjustable stock or brace’s adjustment latch to function properly.

Check out custom stocks and braces here.

Includes Carbine Buffer

This buffer tube assembly includes a 3.0-ounce Carbine recoil buffer. It’s compatible with most calibers that are currently available for chambering in 5.56/.223 receivers, including 300 Blackout and 6.5 Grendel. This kit will also work with our AR9 80% lowers and any retail-bought 9mm lowers, but we recommend investing in a heavier (8.0-ounce) buffer.

Buffer Installation Instructions

Installing the buffer assembly is relatively simple. You will need an Armorer’s Wrench to get the job done. If you’re also installing your lower parts kit, we recommend buying a set of roll pin punches.

Guide: How to Install The AR Buffer and LPK

Need an Upper Assembly?

If you’re completing a custom AR build with this buffer tube assembly, be sure to check out our barreled uppers. Rifle and pistol configurations are available in the most popular AR calibers, and each includes a bolt carrier and charging handle.

Buy a Barreled Upper Assembly Here.