SmythBusters: Mounting Optics on Handguards

Published on September 17, 2025
Duration: 11:27

This video from Brownells' Smithbusters series demonstrates the critical impact of optic mounting location on an AR-15's accuracy. Hosts Steve and Caleb test mounting optics on the handguard versus the receiver, showing significant point of impact shifts and group opening after simulated stress. They conclude that mounting optics on the receiver is essential for maintaining zero and accuracy, especially in demanding scenarios.

Quick Summary

For optimal accuracy and zero retention on an AR-15, optics should always be mounted directly onto the receiver's Picatinny rail. Mounting on the handguard, especially bridging the gap, can lead to significant point of impact shifts and degraded performance due to handguard flex.

Chapters

  1. 00:00Introduction: Optic Mounting Mythbusters
  2. 00:37Baseline: Optic Mounted on Receiver
  3. 01:55First Group: Receiver Mount Baseline
  4. 02:36Second Group: Optic Moved to Handguard
  5. 03:48Simulating Stress: Banging the Handguard
  6. 04:10Third Group: Handguard Mount After Stress
  7. 05:55Test 2: LPVO Bridging the Gap
  8. 06:29LPVO Group: Bridging the Gap
  9. 07:29LPVO Group After Handguard Stress
  10. 09:44Conclusion: Why Receiver Mounting is Crucial

Frequently Asked Questions

Where is the best place to mount an optic on an AR-15 for accuracy?

For optimal accuracy and zero retention on an AR-15, optics should always be mounted directly onto the receiver's Picatinny rail. Mounting on the handguard, especially bridging the gap, can lead to significant point of impact shifts and degraded performance.

What happens if you mount an AR-15 optic on the handguard?

Mounting an AR-15 optic on the handguard can cause accuracy issues, including larger group sizes and significant point of impact shifts, particularly after the firearm experiences stress or vibration. This is because handguards can flex independently of the receiver.

Does stressing an AR-15 with an optic on the handguard affect its zero?

Yes, stressing an AR-15 with an optic mounted on the handguard can significantly affect its zero. Tests show that impacts can shift by several inches after the rifle is bumped or jostled, making it unreliable for accurate shooting.

Why is bridging the gap between an AR-15 receiver and handguard bad for optic mounting?

Bridging the gap means mounting an optic across both the receiver and the handguard. This is detrimental because the handguard can flex or move independently of the receiver, causing the optic to shift its point of aim and degrade accuracy.

Related News

All News →

More Tactical & Gear Videos You Might Like

More from Brownells, Inc.

View all →