How to Remove and Replace Your Buffer Tube

15th Jun 2020

With its completely modular platform, the AR-15 is one of the most versatile guns on the market. Lightweight, accurate and dependable, this weapon is popular with shooters across the nation, and it's highly customizable. AR-15s are easy to work on once you know the steps, and there are many aftermarket improvements you can install at home using simple tools. One of the most common upgrades that AR owners pursue is that of the buffer tube and spring.

Why Remove and Replace the Buffer Tube of an AR-15?

The buffer assembly sits behind the bolt carrier group (BCG) inside the buttstock of your weapon. When you fire, the bolt drives the buffer and spring into the buffer tube to absorb recoil. That spring then pushes the BCG back into place to seat the next round. If you plan to change the length of your buttstock, switch from a fixed to a collapsible buttstock, install a sling adapter or replace your factory components to improve performance, you'll need to remove your buffer tube.

Steps to Remove the Buffer Tube

Any time you take your gun apart, be sure you have an empty magazine well and visually confirm that there is nothing in the chamber. Be sure your workspace is clean and large enough for you to work comfortably.

1. Remove the Buffer and Buffer Spring

After breaking your gun down into the upper and lower receivers, look at your lower. All AR-15s have buffers and buffer springs loaded into the buffer tube, and those parts need to come out before you disassemble your buttstock. To remove them, push the buffer slightly into the stock to release the tension on the retaining pin that holds it in place. With your other hand, push the retaining pin down while you guide the buffer and spring out of the buffer tube, then set them aside.

2. Remove the Buttstock

Between the buttstock and receiver is the detent spring and detent — tiny pieces that can quickly get away from you if you aren't careful. When removing your buttstock, you'll want to maintain some pressure on the spring until you're ready to catch it and put it aside. The steps for stock removal depend on whether you have a fixed or positionable setup:

  • Fixed buttstocks: If you have a fixed (non-collapsible) buttstock on your AR, you will need to grab a flathead screwdriver. Search the gun's buttplate for a screw. If you don't see one, check and see if you need to remove a cover or lid first. When you are ready to unscrew your buttstock, use your other hand to keep the stock pressed against the receiver so the screw stays inside. Once loose, the stock should slide off, letting you catch and retain the detent and spring.
  • Collapsible buttstocks: To remove a collapsible stock, you will need a castle nut wrench or an armorer's tool. Instead of a screw, you will use your wrench to unscrew the castle nut — a large nut located where the stock joins the lower. While loosening the nut, keep a firm hold on the receiver lock plate (the washer between the nut and your rifle) to keep the detent pin contained. After loosening the nut, you can slide the lock plate back to remove the spring and detach the buttstock.

3. Remove the Buffer Tube

With the stock removed, your buffer tube is ready for removal. Get a firm grip, loosen yours by hand and that's it. When replacing a buffer tube, first check whether your lower uses commercial or Mil-Spec components — military buffer tubes measure 1.146" where the stock slides on, while commercial tubes measure 1.170". Your stock and buffer tube must be of the same variety for proper fit and function.

Check with your calipers again to ensure you have the right size buffer tube for your stock, then line up the threads and tighten it on, being careful not to overtighten. You're now ready to replace your buffer, buffer spring and stock.

Replace and Upgrade Your Buffer Tubes With Wing Tactical

At Wing Tactical, we carry a wide selection of buffers, buffer tubes and springs for upgrading your AR-15 buffer assembly and improving your gun's function. For help choosing the right components for your firearm, send us an email today.