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Adjustable Carbine Stock & Buffer Tube Assembly

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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.




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Shipping Restrictions

Shipping of various parts and/or accessories are prohibited to states and locales (ie New Jersey, California, New York, etc…) with restrictions against certain parts and/or accessories or "assault weapons" (i.e. states with high-capacity magazine restrictions, manufacturing of semi-automatic weapons, etc..). It is your responsibility to be aware of your local firearms laws before purchasing from our website or machining a firearm. We try our best to keep our shipping page current, but laws change daily. only ships within the United States. Federal legislation dictates we cannot ship our products internationally.

.223 Wylde
.300 AAC Blackout

We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, Hawaii, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.