Glock 31

The Glock 31 is a semi-automatic pistol manufactured by Glock Ges.m.b.H. in Austria. Designed by Gaston Glock, the firearm is a full-sized derivative of the Glock 22. It was developed to utilize the .357 SIG cartridge, a bottlenecked round introduced in 1994 to replicate the ballistics of .357 Magnum loads. The handgun follows the design principles established by the original Pistole 80, which entered Austrian military and police service in 1982.

The pistol utilizes a short-recoil-operated, locked-breech system with a vertically tilting barrel. The frame is constructed from "Polymer 2," a high-strength nylon-based synthetic, while the slide is milled from a single block of steel treated with ferritic nitrocarburizing for corrosion resistance. The "Safe Action" system incorporates three independent internal safety mechanisms—trigger, firing pin, and drop safeties—in place of an external manual switch. Specific to this model, the magazine body includes an internal rib on each side with follower cutouts to facilitate the feeding of bottlenecked ammunition. The design allows for conversion to .40 S&W through a barrel replacement, as both cartridges share compatible frame and slide dimensions.

The Glock 31 has been produced across several design iterations, including the third-generation "Rough Textured Frame 2" (RTF2) variant featuring scalloped slide serrations and modified grip checkering. While the manufacturer supplies pistols to agencies in at least 48 countries, including the Federal Bureau of Investigation and various United States police agencies, the company announced a production adjustment in October 2025. This initiative involves ceasing the manufacture of over thirty variants, including the Glock 31, to focus on specific single-stack models and a new "V" series featuring redesigned internal components intended to prevent unauthorized automatic conversions.