How to Inspect & Prep an AR-15 Lower Receiver Presented by Larry Potterfield of MidwayUSA

Published on July 19, 2018
Duration: 1:18

This guide details the essential inspection and preparation steps for an AR-15 lower receiver before assembly. It emphasizes cleaning out detent and pin holes using specific drill bit sizes and a pin vise, and cleaning pistol grip screw threads with a tap. Proper prep work ensures easier assembly and a functional firearm.

Quick Summary

Essential AR-15 lower receiver prep involves a careful inspection for defects, followed by cleaning detent and pin holes with specific drill bits (#40 for pivot/takedown, #22 for safety, #23 for hammer/trigger) in a pin vise. Cleaning pistol grip screw threads with a 1/4-28 tap and oil also aids assembly.

Chapters

  1. 00:04Importance of Prep Work
  2. 00:08Lubricating Pins for Assembly
  3. 00:13Initial Inspection
  4. 00:22Cleaning Detent and Pin Holes
  5. 00:31Using #40 Drill Bit for Pivot/Takedown Holes
  6. 00:43Using #22 Drill Bit for Safety Detent
  7. 00:47Using #23 Drill Bit for Hammer/Trigger Pins
  8. 00:55Final Chip and Finish Check
  9. 01:00Cleaning Pistol Grip Screw Threads
  10. 01:12Ready for Assembly

Frequently Asked Questions

What are the key steps for preparing an AR-15 lower receiver before assembly?

Before assembling an AR-15 lower receiver, it's crucial to perform a thorough inspection for defects. You must then clean out any burs, chips, or finish buildup from the detent and pin holes using specific drill bits and a pin vise. Finally, clean the pistol grip screw threads with a tap and tapping oil for easier installation.

What specific drill bit sizes are recommended for cleaning AR-15 lower receiver pin holes?

For AR-15 lower receiver pin holes, a #40 drill bit is used for the pivot and takedown detent holes. A #22 drill bit is recommended for the safety detent hole, and a #23 drill bit is used for the hammer and trigger pin holes. These are used gently with a pin vise.

How do you clean the threads for the pistol grip screw on an AR-15 lower receiver?

To clean the threads for the pistol grip screw on an AR-15 lower receiver, you should use a 1/4-28 tap along with tapping oil. This process helps remove any debris or imperfections, making the installation of the screw smoother and easier.

Why is it important to inspect an AR-15 lower receiver before assembly?

Inspecting an AR-15 lower receiver before assembly is vital to identify any potential problems or manufacturing defects. Finding these issues early allows you to address them before they complicate the build process or compromise the firearm's functionality and safety.

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