Glock G17 Gen5 MOS 9mm
Model: PA175S203MOS
Glock G17 Gen5 MOS 9mm
Model: PA175S203MOS
Full Specifications
About This Firearm
The G17 Gen5 MOS is the optic-ready version of the most widely issued law enforcement sidearm in the country. Same 4.49" barrel, same 17-round capacity, same 24.87 oz weight as the standard G17 Gen5. The difference is the Modular Optic System cut on the slide, which accepts red dots via adapter plates without aftermarket milling. The MOS system was Glock's answer to a market that moved toward optic-ready pistols while the standard G17 stayed iron-sight only.
Glock's MOS adapter plates sit between the optic and the slide, which raises the dot higher than a direct-mill setup. Aftermarket plates from C&H Precision and Forward Controls Design seat lower and hold zero more reliably under recoil. This is a known trade-off that most serious red-dot shooters address. The 6.65" sight radius still works as backup through the optic window if the battery dies. The 5.8 lb trigger, three magazines, nDLC slide finish, and Picatinny rail carry over unchanged from the non-MOS model.
Practical tip: if you buy the G17 MOS specifically to mount a red dot, order an aftermarket mounting plate and suppressor-height sights at the same time. The factory plates work but sit high, and the standard iron sights will not co-witness through most optics. Doing both upgrades at once saves a trip to the gunsmith. The HK VP9 and CZ P-10 F also ship optic-ready if Glock's plate system is a dealbreaker.
Best For
Strengths & Limitations
- Factory optic cut eliminates the need for aftermarket slide milling and preserves the factory warranty. The MOS system accepts most common red dot footprints via included adapter plates.
- Inherits the G17 platform's aftermarket depth. More holsters, sights, triggers, and replacement parts are available than for any competing handgun.
- Three magazines in the box instead of the usual two. The G17 platform also accepts all Glock 17-round and aftermarket 33-round magazines.
- The MOS adapter plates add 3-4mm of height between the optic and slide, raising the dot above what a direct-mount achieves. Most experienced red dot shooters replace the plates with aftermarket options from C&H Precision or Forward Controls Design for a lower, more secure mount.
- The 5.8 lb trigger pull is heavier than the HK VP9 at 5.4 lbs and notably heavier than the CZ P-10 F at roughly 4.5 lbs. The trigger works but does not impress for a full-size pistol.
Category Rankings
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Frequently Asked Questions
What is the difference between the G17 Gen5 MOS and the standard G17 Gen5?
The MOS adds an optic-ready slide cut with included adapter plates and a slightly longer 6.65" sight radius (vs 6.5" on the standard). Everything else is identical: same barrel, same trigger, same weight, same magazines. The standard G17 cannot mount a red dot without aftermarket slide milling. If you have no plans for a red dot, the standard G17 Gen5 is the same gun for less.
What red dot sights fit the G17 Gen5 MOS?
Glock includes four adapter plates covering most common footprints: Trijicon RMR, Leupold DeltaPoint Pro, Holosun 507C/508T, and others. The RMR footprint (shared by the Holosun 507C) is the most popular choice among owners. For the best mount, many shooters replace Glock's plate with a machined aftermarket plate from C&H Precision that seats the optic lower and uses more screws for security under recoil.