Smyth Busters: Can Over-Lubrication Cause an AR-15 To Malfunction?

Published on April 6, 2021
Duration: 4:10

This video debunks the myth that over-lubrication is harmless for an AR-15. Experts Steve and Caleb explain how excess oil can attract debris, increase bolt velocity leading to excess head thrust, and cause carbon buildup behind gas rings. While under-lubrication is worse, over-lubrication can cause specific mechanical failures, especially in cold weather for bolt-action firing pins.

Quick Summary

Over-lubrication can cause AR-15 malfunctions by attracting dirt and debris, increasing bolt velocity leading to excess head thrust, and causing carbon buildup behind gas rings. While under-lubrication is worse, excessive oil can indeed cause specific mechanical failures.

Chapters

  1. 00:00Intro: Over-Lubrication Myth
  2. 00:15Dust & Dirt Attraction
  3. 00:48Bolt Velocity & Head Thrust
  4. 01:55Carbon Buildup & Gas Rings
  5. 02:17Bolt-Action Cold Weather Issues
  6. 03:01Conclusion: Over-Lubrication is Real

Frequently Asked Questions

Can too much oil cause an AR-15 to malfunction?

Yes, over-lubrication can cause AR-15 malfunctions. Excess oil attracts dirt and debris, increases bolt velocity leading to excess head thrust, and can cause carbon buildup behind gas rings, potentially seizing the rifle.

What are the risks of over-lubricating an AR-15?

Over-lubrication can lead to malfunctions by attracting contaminants, increasing bolt velocity and head thrust, and causing carbon buildup in the bolt carrier. This can result in feeding, extraction, or ejection failures.

How does over-lubrication affect bolt velocity in an AR-15?

Excessive oil in the chamber reduces friction on the cartridge casing, allowing the bolt to travel faster. This increased bolt velocity can lead to excessive head thrust, impacting the bolt face harder than intended.

Can cold weather make over-lubrication problems worse?

Yes, cold weather can exacerbate lubrication issues. Excess grease in firing pin channels of bolt-action rifles can become sluggish, leading to light strikes. While not explicitly detailed for AR-15s, extreme cold can affect lubricant viscosity.

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