LMT Carrier - Under torqued Carrier Key Screws

Published on July 18, 2024
Duration: 1:03

This video demonstrates a critical inspection for LMT bolt carrier groups, specifically checking the torque on the carrier key screws. Using a Wheeler FAT Wrench, the instructor performs a breakaway test at 20 and 30 inch-pounds to identify broken or under-torqued screws. The video highlights the importance of this check to prevent potential failures and outlines options for resolution, including contacting the manufacturer or performing a replacement and proper staking.

Quick Summary

To check for under-torqued carrier key screws on an LMT bolt carrier group, use a torque wrench set to 30 inch-pounds. If the screws move at this setting, they are not properly secured. A prior check at 20 inch-pounds can identify broken screws. This test is crucial for ensuring bolt carrier group reliability.

Chapters

  1. 00:00Introduction and Bolt Carrier Group Inspection
  2. 00:06LMT Non-Enhanced Carrier Example
  3. 00:13Breakaway Test Procedure
  4. 00:20Using the Wheeler FAT Wrench
  5. 00:22Torque Settings (20 and 30 inch-pounds)
  6. 00:28Identifying Loose Screws
  7. 00:36Staking Quality vs. Torque
  8. 00:41Importance of Torque Testing
  9. 00:45Next Steps and Resolution Options
  10. 00:58Conclusion

Frequently Asked Questions

How do you check if the carrier key screws on an LMT bolt carrier group are properly torqued?

You perform a breakaway test using a torque wrench. First, set the wrench to 20 inch-pounds to check for broken screws. If none break, increase the setting to 30 inch-pounds to ensure the screws are adequately torqued and not loose.

What are the risks of under-torqued carrier key screws on a bolt carrier group?

Under-torqued carrier key screws can loosen over time, leading to potential malfunctions or failure of the bolt carrier group. This can compromise the reliability and function of the entire firearm.

What tools are needed for a carrier key screw torque check?

You will need a bit driver and a torque wrench capable of measuring low inch-pound values, such as the Wheeler FAT Wrench. Ensure you have the correct bits for the carrier key screws.

What should you do if carrier key screws are found to be under-torqued?

If screws are found to be under-torqued, you have options. You can contact the manufacturer (LMT in this case) to see if they will resolve the issue, or you can replace the carrier key and screws yourself and properly stake them.

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