Primary Arms GLx MD-21 | Unboxing & Overview

Published on August 5, 2025
Duration: 5:15

This video provides an unboxing and overview of the Primary Arms GLx MD-21 Red Dot sight. It details the included accessories, how to mount and adjust the optic, and demonstrates its various features, including multi-reticle options, solar fail-safe, and night vision compatibility. The presenter highlights the optic's brightness and durability for tactical applications.

Quick Summary

The Primary Arms GLx MD-21 Red Dot sight offers a solar fail-safe, Auto Live function, and 12 brightness settings, including night vision compatibility. It features multiple reticle options, such as the ACSS CQB, which can be cycled by holding the minus button.

Chapters

  1. 00:00Introduction and Unboxing
  2. 00:12Contents of the Package
  3. 01:18Optic Overview and Features
  4. 01:38Battery Compartment and Powering On/Off
  5. 02:00Mount Adjustment and Riser Installation
  6. 02:53Viewing the Reticle and Brightness
  7. 03:04Multi-Reticle Options Demonstration
  8. 03:45Daytime Brightness Test
  9. 04:04Additional Features: Auto Live, Durability
  10. 04:24Battery Life and Brightness Settings
  11. 04:43Night Vision Compatibility
  12. 04:53First Impressions and Conclusion

Frequently Asked Questions

What are the key features of the Primary Arms GLx MD-21 Red Dot?

The Primary Arms GLx MD-21 features a solar fail-safe, Auto Live function for battery conservation, multi-reticle options (including ACSS CQB), 12 brightness settings with night vision compatibility, and is shockproof and waterproof.

How do you adjust the mount height on the Primary Arms GLx MD-21?

To adjust the mount height, you remove the four screws securing the mount to the optic. An optional spacer can be added between the optic and mount for increased height. Longer screws are provided for use with the spacer.

How do you cycle through the different reticle options on the GLx MD-21?

To cycle through the reticle options on the Primary Arms GLx MD-21, press and hold the minus (-) button. This will cycle through the available reticles, such as the ACSS CQB, circle/chevron, chevron/dots, and just the chevron.

What is the battery life and brightness of the Primary Arms GLx MD-21?

The GLx MD-21 boasts an estimated 1-year battery life and offers 12 brightness settings. The lowest three settings are compatible with night vision devices.

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