How to Install a BCM QD End Plate on Your AR-15

By Shop Tactical Gear & Holsters丨Guerrilla Tactical | Published: 2026-10-21

Category: How-to Guides

Install a BCM QD End Plate on your AR-15 in minutes. This guide covers tools, steps, and common mistakes for a secure QD sling mount.

Quick answer

Install a BCM QD End Plate by replacing your standard AR-15 end plate during a buffer tube swap or disassembly. No special tools required beyond a castle nut wrench and a punch.

What you need before starting

A standard AR-15 armorer's wrench (castle nut wrench), a punch or small flathead screwdriver, and a non-marring hammer. You'll also need a vise or a sturdy work surface to hold the lower receiver steady.

The BCM QD End Plate is machined steel and fits any mil-spec buffer tube. It accepts standard push-button QD sling swivels for rear two-point or single-point sling mounting.

When to install the QD end plate

The best time is during a buffer tube upgrade or when you're already removing the stock. If you only want to swap the end plate, you'll need to remove the stock and buffer tube anyway, so plan accordingly.

If your rifle has a staked castle nut, you'll need to break the staking first. This is normal and doesn't damage the receiver if done carefully.

Step-by-step installation

1. Remove the stock and buffer tube: Separate the upper and lower receivers. Remove the stock by loosening the adjustment lever and sliding it off. Unscrew the buffer tube nut (castle nut) counterclockwise with an armorer's wrench, then slide off the buffer tube and spring. Keep the buffer retainer pin and spring in place; they can fall out easily.
2. Remove the old end plate: Slide the original end plate off the buffer tube threads. Note its orientation—the indexing tab should align with the lower receiver's tang slot. Don't lose the small detent pin and spring for the safety selector if they fall out.
3. Install the BCM QD End Plate: Slide the BCM QD End Plate onto the buffer tube threads with the QD socket facing the rear (toward the stock). Align the indexing tab with the slot on the lower receiver. Make sure the QD socket is clear of the buffer tube and stock; it should rotate freely.
4. Reinstall the buffer tube and castle nut: Slide the buffer tube back into the lower receiver, ensuring the buffer retainer pin engages correctly. Thread the castle nut on by hand, then tighten it to 35-40 ft-lbs with an armorer's wrench. Over-tightening can crush the end plate or strip the threads; use a torque wrench if available.
5. Stake the castle nut (optional but recommended): Use a punch and hammer to dimple the castle nut into the notch on the buffer tube. This prevents the nut from loosening under recoil. Only stake after confirming the end plate is properly aligned and the QD socket faces the correct direction.
6. Reattach the stock and test: Slide the stock back onto the buffer tube, adjust to your preferred length, and lock it. Attach a QD sling swivel to the BCM end plate and give it a firm tug to confirm it locks securely. If the swivel doesn't click in or feels loose, check that the QD socket is clean and free of debris.

Product used in this guide

BCM QD End Plate: The BCM Quick Detach (QD) End Plate is machined steel and compatible with standard QD push-button sling swivels. It provides a durable, secure rear sling attachment point without adding extra weight or bulk to your AR-15.
BCM QD End Plate