Brownells - Changing Standard Butt Stock To Collapsible

Published on August 20, 2012
Duration: 3:57

This guide details the process of converting an AR-15 from a fixed rifle stock to a collapsible carbine stock, as demonstrated by professional gunsmith Eric Kiesler. It covers disassembly, removal of the old extension tube, identification of Mil-spec vs. commercial variations, installation of the new components, and proper torquing procedures for a secure and reliable build.

Quick Summary

Convert your AR-15 from a fixed stock to a collapsible one with this expert guide. Learn to properly remove the old stock, identify Mil-spec vs. commercial receiver extension tubes, install new components, and apply the correct 38-42 ft-lbs torque to the extension nut for a secure build.

Chapters

  1. 00:00Introduction and Initial Disassembly
  2. 00:24Removing the Fixed Stock
  3. 01:01Removing the Extension Tube
  4. 01:25Carbine Extension Tube Variations
  5. 02:18Installing the Carbine Stock
  6. 03:00Torquing and Final Assembly

Frequently Asked Questions

What are the key differences between Mil-spec and Commercial-spec AR-15 receiver extension tubes?

Mil-spec AR-15 receiver extension tubes are approximately 0.020 inches larger in diameter than commercial-spec tubes. This difference affects the fit of stocks designed for each standard, so it's important to match the tube and stock specifications.

What is the correct torque specification for an AR-15 receiver extension nut?

For professional builds, the receiver extension nut on an AR-15 should be torqued to between 38 and 42 foot-pounds (ft-lbs). Using a torque wrench ensures proper tightness and prevents damage or loosening.

What tools are essential for converting an AR-15 stock from fixed to collapsible?

Essential tools include a vise, an AR-15 magazine well filler block for stability, a Brownells buttstock wrench for the stock screw, and a receiver extension wrench for the buffer tube. A torque wrench is recommended for final tightening.

What common mistakes should be avoided during an AR-15 stock conversion?

Key mistakes to avoid include losing the small takedown pin spring and detent during disassembly, not properly retaining the pivot pin spring with the end plate, and failing to torque the receiver extension nut correctly, which can lead to instability.

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