The Glock 31 is a full-size pistol chambered in .357 SIG, commonly used by law enforcement and tactical units where the cartridge's high velocity and flat trajectory are priorities. Its 4.49-inch Glock Marksman Barrel (GMB) uses advanced rifling and tighter tolerances for improved accuracy. Capacity is 15+1. The nDLC finish on the slide and barrel resists corrosion and wear, and the low bore axis reduces muzzle flip for faster follow-up shots. The polymer frame stays lightweight under hard use.