Red dot mounts for Glock 21

Adding a red dot to the Glock 21 gives you a single focal plane on the full-size .45 ACP — faster acquisition than iron sights on a platform where the wider bore axis already requires deliberate sight alignment for follow-up shots.

A dovetail red dot mount fits directly into the rear sight dovetail on your pistol — the same cut that holds the factory rear sight. The mount replaces the rear sight and positions the optic directly above the slide in the sighting plane. Installation requires no gunsmithing and no machining: remove the rear sight, seat the mount in the dovetail, and tighten the setscrew. The modification is fully reversible — if you want to return to iron sights, you reinstall the factory rear sight and the slide is unchanged.

Compatibility depends on the specific model and configuration — always check the individual product page before ordering.