Selected Handgun Detail

Manufacturer
	Glock Ges.m.b.H. More Info

About the Gun

Fifth-generation full-size pistol in .45 ACP incorporates the Modular Optic System with a factory-milled slide that accepts miniature reflex sights through interchangeable adapter plates without requiring additional machining. It features a polymer frame without finger grooves, interchangeable backstraps for grip customization, a modestly flared magazine well, an ambidextrous slide stop lever, an nDLC finish on the slide, front slide serrations, and the Glock Marksman Barrel with conventional rifling and a revised crown profile. The overall configuration maintains the established short-recoil, locked-breech operating system with a striker-fired trigger mechanism and standard fixed sights.

Production

Production ran from 2023 through 2025.

Market value

MSRP at production was $745. Used market values for very good condition examples range $500–$550.

Cartridge Specifications
Cartridge:	.45 Automatic
Alias:	.45 Automatic Colt Pistol (ACP)
More Info

Analysis

The Glock 21 Gen5 MOS provided updated ergonomics and optics capability on the large-frame .45 ACP platform. Released exclusively as an MOS model, the factory-integrated slide cut and front slide serrations were present from the initial release, preserving the pistol’s operating characteristics while providing direct mounting for red dot sights and improved slide manipulation. Production remained limited relative to the 9mm Gen5 models, and the platform saw continued use in defensive and duty applications until Glock phased out most Gen5 models in late 2025. On the secondary market these optics-ready units have retained steady demand due to the combination of .45 ACP power and modern sighting options.