Red dot mounts for Glock 21

(11 products)

This collection contains red dot mounts for the Glock 21. The mount goes into the rear sight dovetail in place of the rear sight. You fit a red dot without milling and without permanent changes, and you can put the rear sight back at any time. Every mount takes one footprint or a group of footprints, so you choose it by the footprint of your red dot. The mounts are not for Optics Ready variants with a factory optic cut.

Mounts in this collection

Glock 21 red dot mount: RMSc footprint, from Shield Sights.
Red dot mount Glock models [G17, G19, G26 & other]: RMR, RMSc, K-series, DPP, Docter and RTS footprints, from Angry Bear, EGW, Holosun, Outer Impact, Toni System and Zendl.

Each mount fits the models named in its title. Make sure your model and variant are among them.

Material

Zendl makes its mounts from steel. Outer Impact, Toni System, EGW, Angry Bear and Holosun make their mounts from aluminium. An aluminium mount is lighter. A steel mount is heavier and robust.

Installation

Drift the rear sight out of the dovetail with a sight pusher or a punch. Push the mount into the dovetail and fix it. Then screw the red dot onto the mount with a drop of threadlocker on each screw. See Installation tools.

All mounts at a glance

Mount	Footprints	Maker
Glock 21 red dot mount	Shield RMSc footprint	Shield Sights
Red dot mount Glock models [G17, G19, G26 & other]	Holosun K-series footprint, Shield RMSc footprint	Angry Bear
Red dot mount Glock models [G17, G19, G26 & other]	Shield RMSc footprint	Zendl
Red dot mount Glock models [G17, G19, G26 & other]	Trijicon RMR footprint, type S [RMSc, DPP, K-series footprint]	EGW
Red dot mount Glock models [G17, G19, G26 & other]	type A [RMSc, DPP, Docter footprint], type B [RMR & RTS footprint]	Toni System
Red dot mount Glock models [G17, G19, G26 & other]	type C [RMR, RTS, Docter footprint], type S [RMSc, DPP, K-series footprint]	Outer Impact
Red dot mount Glock models [G17, G19, G26 & other]	type D [RMR & Docter footprint]	Holosun

Which red dot for which footprint

Trijicon RMR: for example the Holosun 407C, 507C and 508T, Olight Osight and Vector Optics Frenzy-X. See Red dots with Trijicon RMR footprint.
Shield RMSc: Shield red dots, the Holosun EPS Core, Olight Osight K, S and SE and Vector Optics Frenzy-S. See Red dots with Shield RMSc footprint.
Holosun K-series: the Holosun 407K and 507K, EPS Carry and SCS Carry. See Red dots with Holosun K-series footprint.
Leupold DPP: for example the Holosun SCS 320, Olight Osight SE DPP and Vortex Defender ST and XL. See Red dots with Leupold DPP footprint.
Docter: also called Vortex Venom or Noblex, for example the Vector Optics Frenzy 1x17x24 and Frenzy-X 1x20x28. See Red dots with Docter footprint.
C-More RTS: the C-More RTS, the Toni System ZR, ZV and ZX and the Vector Optics Frenzy Plus. See Red dots with C-More RTS footprint.

For all mounts of this brand, see Red dot mounts for Glock models.

Frequently asked questions

Can I put a red dot on my Glock 21 without an optic cut?

Yes. The mount goes into the rear sight dovetail in place of the rear sight. No milling and no permanent changes.

Can I install the mount at home?

Yes, if you have a sight pusher or a punch.

Drift the rear sight out of the dovetail.
Push the mount into the dovetail and tighten it.
Screw the red dot onto the mount with a drop of threadlocker on each screw.

Which red dots will fit?

It depends on the mount you choose. The mounts in this collection take the Trijicon RMR, Shield RMSc, Holosun K-series, Leupold DPP, Docter and C-More RTS footprints. Find the footprint of your red dot in its specifications and take the mount that names it and your model.

My Glock 21 is Optics Ready. Will these mounts fit?

No. A pistol with a factory optic cut takes an optic plate, not a mount.