The G19 Gen5 MOS adds a factory optic cut to the standard G19 Gen5 while keeping the same 4.02" barrel, 15-round capacity, and 7.28" overall length. The slide weighs 23.81 oz, only 0.18 oz more than the standard model's 23.63 oz. Glock includes adapter plates for Trijicon RMR, Holosun, Leupold DeltaPoint Pro, and other common red dot footprints. If you plan to run a dot on a compact 9mm and want Glock's parts ecosystem behind it, the MOS is the straightforward path.

The adapter plate system is the MOS platform's known weakness. The plates sit 3-4mm between the slide and optic, raising the dot higher than a direct mill. Aftermarket plates from C&H Precision and CHPWS eliminate most of that gap. The Kimber KDS9c and Walther PDP Compact both offer direct-mount optic cuts from the factory without adapter plates, giving a lower optic sit and tighter tolerances at the slide-to-optic interface.

For first-time red dot users, replace the stock plastic sights with suppressor-height night sights before mounting an optic. The factory sights sit too low to co-witness through a mounted dot, so a dead battery or broken optic leaves you without backup irons. Ameriglo and Trijicon both make drop-in options that clear common red dot housings.