AR-15/M4 Firearm Maintenance: Part 4 Reassembly

Published on October 28, 2013
Duration: 2:02

This video provides a detailed, step-by-step guide on reassembling the AR-15/M4 platform, focusing on the bolt carrier group and final upper/lower receiver integration. It emphasizes correct orientation of parts like the cam pin and bolt for proper function. The guide concludes with a crucial function test to ensure the rifle operates safely and correctly after reassembly, a key aspect of firearm maintenance.

Quick Summary

Reassemble the AR-15 bolt carrier group by inserting the bolt into the carrier, aligning the cam pin hole, and inserting the cam pin. Then, install the firing pin and its retaining pin. Reinstall the charging handle, followed by the bolt carrier group. Finally, join the upper and lower receivers with the pivot and takedown pins, and perform a function test.

Chapters

  1. 00:00Introduction to Reassembly
  2. 00:08Reassembling the Bolt Carrier Group
  3. 00:10Inserting the Bolt into the Carrier
  4. 00:21Installing the Cam Pin
  5. 00:37Installing the Firing Pin
  6. 00:43Reinstalling the Firing Pin Retaining Pin
  7. 00:50Inserting the Charging Handle
  8. 00:57Reinstalling the Bolt Carrier Group
  9. 01:08Aligning Upper and Lower Receivers
  10. 01:10Inserting Pivot and Takedown Pins
  11. 01:14Final Function Test
  12. 01:20Confirming Safety Operation
  13. 01:24Conclusion and Resources

Frequently Asked Questions

How do you correctly reassemble the AR-15 bolt carrier group?

Begin by inserting the bolt into the carrier, ensuring the extractor is on the right. Align the bolt's hole with the carrier's cutout and insert the cam pin. Rotate the cam pin 90 degrees, then insert the firing pin and its retaining pin. Finally, install the charging handle.

What is a common mistake when installing the cam pin on an AR-15?

A common mistake is incorrect orientation. The AR-15 bolt is designed to accept the cam pin from only one direction. If you experience difficulty, double-check that the bolt is oriented correctly before attempting installation.

How do you ensure the AR-15 is properly reassembled after maintenance?

After reassembling the bolt carrier group and joining the upper and lower receivers, perform a final function test. Cycle the bolt several times and confirm that the safety mechanism operates correctly to ensure the rifle is safe and functional.

Where can I find tools for AR-15 maintenance and gunsmithing?

Brownells.com is a recommended resource for a wide selection of gunsmithing tools and accessories. They offer a 100% lifetime guarantee on their products, making them a reliable source for firearm maintenance needs.

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