Glock MOS

Glock MOS (Modular Optic System) pistols come from the factory with a milled slide and included adapter plates, ready to mount a red dot sight without any gunsmithing. We stock Glock MOS models across the full lineup — from the compact G19 MOS to the full-size G17 MOS and long-slide G34 MOS — for carry, competition, and home defense builds.

Read our Glock MOS Buying Guide ↓

What Is Glock MOS?

MOS stands for Modular Optic System. Glock MOS pistols have a factory-milled cut in the slide with a recessed mounting platform. Each MOS pistol ships with a set of adapter plates that accommodate the most popular red dot footprints — including the Shield RMS, Trijicon RMR, Docter, and Leupold DeltaPoint Pro. No milling, no gunsmiths, no additional cost. Mount your red dot, co-witness your irons, and go.

MOS Models Available

Glock 17 MOS — The full-size 9mm. Best for home defense, open carry, and competition where capacity and sight radius matter. The G17 MOS is one of the most popular competition handguns in Production and Carry Optics divisions.

Glock 19 MOS — The compact 9mm. Our best-selling MOS model. Balances concealability with a large enough slide to mount most red dots without significant height-over-bore issues. The go-to for serious concealed carry with an optic.

Glock 34 MOS — The long-slide competition 9mm. Extended barrel and sight radius, lightened slide cuts, and MOS optics cut. Built specifically for competition shooting. Dominant in USPSA Carry Optics.

Glock 45 MOS — Full-size Gen 5 frame with compact slide. Excellent ergonomics and now with factory optics cut. The preferred duty and carry gun for many professionals.

Glock 40 MOS — The 10mm long-slide MOS. Popular for hunting, bear country carry, and handgun hunters who need an optic-ready powerhouse.

Glock 41 MOS — The .45 ACP long-slide MOS competition pistol. Glock's answer to full-size .45 competition shooting.

Glock 20 MOS / Glock 21 MOS — 10mm and .45 ACP full-size MOS models for buyers who want larger calibers with optics capability.

Which Red Dot Works Best on a Glock MOS?

Trijicon RMR Type 2 — The gold standard for duty and carry use. Extremely robust, battle-proven, and the optic most serious shooters trust for defensive use. Adapter plate included with your MOS pistol.

Holosun 507C / 508T — The best value in the MOS category. Solar-powered backup, large window, and excellent reliability at a lower price point than the RMR. Hugely popular on G19 MOS builds.

Leupold DeltaPoint Pro — Low-profile option with a wide field of view. Popular for competition where weight and sight picture matter more than extreme durability.

What to Know Before You Buy

  • Gen 6 MOS models use a standardized optics footprint that eliminates the need for adapter plates on the most common red dots — a significant upgrade over the Gen 5 MOS system.
  • Holsters for MOS models must be optics-compatible. Standard Glock holsters will not fit an MOS with an optic mounted. Verify your holster accommodates your optic before purchasing.
  • Co-witnessing your iron sights with your red dot is strongly recommended as a backup in case of battery failure or optic damage.
  • All Glock pistols ship to your local FFL dealer. Standard background check procedures apply.

Questions about Glock MOS or which optic is right for your build? Call us at 800-917-7137 or use our live chat — we're happy to help.