Glock made the G45 by grafting a full-size G17 grip onto a compact G19 slide, then cut the slide for optics. The result holds 17+1 rounds in a 7.44-inch frame that weighs 24.52 oz. The MOS system ships with four adapter plates covering the Trijicon RMR, Holosun 407C/507C, Leupold DeltaPoint Pro, and other common footprints. Three magazines in the box means 51 rounds of factory capacity before ordering spares.

The 4.02-inch barrel splits the difference between subcompact carry guns and full-size duty pistols. The full-size grip fills the hand better than a G19 but adds 0.43 inches of grip height (5.47 vs. 5.04 inches), which prints more under clothing. Reviewers consistently describe the G45 as a gun that shoots like a G17 but carries in a duty holster like a G19. The 5.8 lb trigger is standard Gen5 fare with a soft take-up before a defined wall.

The surprising thing about the G45 MOS is how well it works as a first optic-ready pistol. The four-plate system means most buyers find their preferred dot in the box, and the 6.18-inch sight radius with suppressor-height sights provides usable co-witness. The Walther PDP Compact runs a lighter trigger and ships with a direct-mount optic system, but it holds 15 rounds to the G45's 17. The FN 509 Compact MRD matches the optics capability but weighs 2 oz more at 26.6 oz. For shooters who want the G17's capacity in a shorter package with a factory red dot mount, the G45 MOS is a straightforward answer.