Your Cart

3D Printed Guns. 80% Builds. Ultimate Guides.

How to Fix a Collapsible AR15 Stock

If you own an AR-15, you know how important the collapsible stock is for adjusting the length to increase shooting accuracy and comfort.

However, collapsible stocks can sometimes develop issues, such as rattle and shake, or even detachment from the buffer tube. These issues can be frustrating and potentially dangerous, so it’s important to get them fixed, pronto!

how to fix ar15 stock

Fortunately, there are several easy ways to fix a collapsible stock AR-15, depending on the specific issue you’re experiencing.

ar15 collapsible stock area

Some methods involve permanently fixing the stock to the buffer tube, while others involve using devices to restrict movement. In this article, we’ll explore some of the most common issues with collapsible stocks and provide step-by-step instructions for fixing them.

Whether you’re a seasoned AR-15 owner or a beginner, knowing how to fix your collapsible stock can save you time, money, and frustration. With the right tools and techniques, you can easily address common issues and keep your AR-15 functioning smoothly and safely.

Shop Husky Armory

Diagnosing the Problem

When it comes to diagnosing a problem with your collapsible stock AR15, there are a few things to keep in mind. The first step is to identify the type of problem you’re experiencing.

Here are some common AR15 stock issues:

  • The stock won’t extend or retract
  • The stock is loose or wobbly
  • The stock won’t lock into place
  • The stock won’t stay in place

If your AR15 collapsible stock won’t extend or retract, the first thing to check is the buffer tube. Make sure it’s properly installed and tightened. If the buffer tube is loose, it can cause the stock to bind. If that doesn’t solve the problem, you may need to replace the buffer spring or the buffer itself.

If your stock is loose or wobbly, check the castle nut. Make sure it’s properly tightened and staked. If the castle nut is loose, it can cause the entire stock assembly to move around. If that doesn’t solve the problem, you may need to replace the buffer tube or the stock itself.

If your stock won’t lock into place, the problem may be with the locking mechanism. Check the latch and make sure it’s not damaged or worn. If the latch is fine, check the detent and spring. If either of those are damaged or worn, they may need to be replaced.

wiggle loose collapsible ar15 stock

If your stock won’t stay in place, the problem may be with the buffer tube. Check to make sure it’s not damaged or worn. If the buffer tube is fine, check the stock itself. The locking mechanism may be worn or damaged, causing the stock to slip out of place.

By identifying the type of problem you’re experiencing, you can take the necessary steps to fix it. In the next section, we’ll go over some common solutions to these problems.

Tools Needed

Before you start fixing your collapsible stock on your AR-15, you need to have the right tools.

Here’s a list of the tools you’ll need:

AR-15 Armorer’s WrenchThis wrench is necessary to remove the castle nut, if you need to remove the buffer tube.
Hex or Torx WrenchesYou’ll need the appropriately sized hex or Torx wrenches for your specific stock.
Drill Bit and Roll PinIf you want to pin your collapsible stock, you’ll need a matching set of drill bit and roll pin.

Please note that most fixed stocks you can buy will not require you to remove the buffer tube. However, if you’re fixing a collapsible stock, you’ll need to remove the buffer tube to access the castle nut.

Having the right tools will make the process much easier and help prevent damage to your AR-15. Make sure you have all the necessary tools before you start fixing your collapsible stock.

Removing the Stock

Removing a collapsible stock from an AR-15 is a relatively simple process. However, it requires some tools and a bit of patience.

buffer tube to ar15 stock castle nut

Here are the steps to follow:

  1. First, ensure that your firearm is unloaded and the safety is engaged.
  2. Next, remove the buffer tube from the lower receiver. This is done by using a wrench to unscrew the castle nut at the end of the buffer tube. You may need to use a vise block to hold the lower receiver in place while you do this.
  3. Once the castle nut is removed, slide the buffer tube and spring off the back of the lower receiver.
  4. With the buffer tube and spring removed, you can now slide the collapsible stock off the buffer tube. Depending on the manufacturer, there may be a small pin or screw that needs to be removed before the stock can be taken off.
  5. Once the stock is removed, you can install your new stock or make any necessary repairs or upgrades.
  6. To reassemble, simply slide the buffer tube and spring back onto the lower receiver and tighten the castle nut. Be sure to torque the castle nut to the correct specification, which is typically between 35-45 ft-lbs.

It’s important to note that while removing a collapsible stock is a relatively easy process, it’s important to take your time and follow the steps carefully to avoid damaging your firearm or injuring yourself. If you’re not comfortable performing this procedure yourself, it’s always best to seek the help of a professional gunsmith.

Inspecting the AR15 Stock Components

Before attempting to fix a collapsible stock on your AR-15, it’s important to inspect the components to identify any issues that may be causing the problem.

Here are the steps to follow:

  • Remove the stock from the buffer tube and inspect it for any cracks, damage, or wear and tear.
  • Check the buffer tube for any signs of damage or corrosion.
  • Inspect the buffer spring and buffer for any damage or wear and tear.
  • Check the castle nut and end plate for any damage or wear and tear.

If you notice any issues with the components, it’s important to replace them before attempting to fix the collapsible stock. Failure to do so could result in further damage to your rifle or even injury to yourself or others.

It’s also a good idea to clean and lubricate the components while you have them removed from the rifle. This will help ensure that they function properly and prevent any future issues with the collapsible stock.

By inspecting the components before attempting to fix the collapsible stock, you can identify any underlying issues and ensure that your rifle is safe and functional.

Repairing the AR15 Stock

If you have a loose or wobbly collapsible stock on your AR-15, there are a few ways to repair it.

buffer tube spring ar15 stock

Here are some possible solutions:

  • Tighten the screw: The first thing you can try is tightening the screw that holds the stock onto the buffer tube. Use a wrench or pliers to tighten it, but be careful not to over-tighten it, as this can damage the threads.
  • Add a shim: If tightening the screw doesn’t work, you can try adding a shim between the stock and the buffer tube. This will help fill any gaps and prevent the stock from wobbling. You can use a piece of rubber or even a business card as a shim.
  • Replace the buffer tube: If the problem persists, you may need to replace the buffer tube. This is a more involved repair, but it will ensure that the stock fits tightly and securely. Make sure to choose a high-quality buffer tube that is compatible with your AR-15.

It’s important to note that if you decide to permanently fix the stock to the buffer tube, you may be violating certain laws and regulations. Make sure to research and understand the laws in your area before attempting this repair.

Reassembling the AR-15

Now that you have removed the collapsible stock from your AR-15, it’s time to reassemble it.

Follow these steps:

  1. Insert the buffer spring into the buffer tube, followed by the buffer.
  2. Slide the buffer tube back into the lower receiver until it clicks into place.
  3. Insert the detent and spring into the buffer tube and screw on the castle nut.
  4. Place the end plate onto the buffer tube and tighten the castle nut against it.
  5. Slide the new collapsible stock onto the buffer tube until it clicks into place.
  6. If necessary, adjust the stock to your desired length using the adjustment lever or button.
  7. Tighten the locking mechanism to ensure the stock stays in place.

Once you have completed these steps, your AR-15 should be fully reassembled and ready to use. Remember to test the stock to ensure it is secure before firing your weapon.

It’s important to note that if you encounter any issues during the reassembly process, it may be best to seek the assistance of a professional gunsmith.

Attempting to fix the issue yourself could result in further damage to your weapon or even injury to yourself.

If you do have any quick questions, feel free to leave a comment below. 3D Gun Builder will do our best to point you in the right direction.

Written By

Cody Y.


Cody is a staff writer for 3D Gun Builder.

Cody brings years of experience in firearms, 80% builds, 3D printing, and internet security.

He owns six 3D printers and enjoys spreading his knowledge of modern day gun smithing around the world.

3D Gun Files

Download over 100+ STLs


Learn 3D Gun Printing

Polymer 80

80% Guides & Tips

Industry News

Stay Up to Date