Glock G31 Gen4
Glock Ges.m.b.H. · Pistol · Discontinued · 2010
Also known as: G31 Gen4, Glock 31 Gen 4
Overview
The Glock G31 Gen4 is the fourth-generation variant of Glock's full-size .357 SIG duty pistol, featuring Gen4 improvements applied to the high-velocity law enforcement platform. Built on the same full-size frame as the Glock 17 and 22, the G31 Gen4 delivers 15+1 rounds of .357 SIG -- a bottleneck cartridge designed to replicate .357 Magnum ballistics in a semi-automatic pistol. The Gen4 adds modular backstraps for customizable grip fit, a dual recoil spring assembly that helps manage the .357 SIG's sharp recoil impulse, a reversible enlarged magazine catch, and the Rough Textured Frame for enhanced grip. With a 4.49-inch (114mm) barrel, the G31 Gen4 propels 125-grain bullets at approximately 1,410 fps (430 m/s) for 748 joules of muzzle energy, providing exceptional barrier penetration capability. Weighing 26.10 ounces (740g) with an empty magazine, the G31 Gen4 was widely adopted by state police and highway patrol agencies that valued the .357 SIG's performance against automotive glass and intermediate barriers.
Specifications
| Weight (empty) | 740 g (26.1 oz) |
| Weight (loaded) | 940 g (33.2 oz) |
| Overall Length | 202 mm (7.95") |
| Barrel Length | 114 mm (4.49") |
| Height | 139 mm (5.47") |
| Width | 32 mm (1.26") |
| Sight Radius | 165 mm (6.50") |
| Action Type | Short Recoil |
| Firing Mechanism | Striker Fired |
| Trigger Type | Safe Action |
| Trigger Pull | 28 N (6.3 lbf) |
| Magazine Capacity | 15 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 430 m/s (1411 fps) |
| Muzzle Energy | 748 J (552 ft·lbf) |
| Effective Range | 50 m (55 yd) |
| Maximum Range | 1800 m (1968 yd) |
| Barrel Rifling | Right Hand |
| Rifling Twist | 400 mm (15.75") |
| Number of Grooves | 6 |
| Frame Material | Polymer |
| Slide Material | Steel |
| Barrel Material | Steel |
| Finish | Tenifer |
Calibers
- .357 SIG · primary — also known as 357 SIG, 9x22mm
Features
- Firing modes: Semi Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Trigger Safety, Firing Pin Safety, Drop Safety
- Features: Polymer Frame, Interchangeable Backstraps, Dual Recoil Spring, Reversible Mag Release, Rough Textured Frame, Hexagonal Rifling, Accessory Rail
Base model
Service history
Operators
- Virginia State Police
- Delaware State Police
- Federal Air Marshal Service
- Texas Department of Public Safety
Production
Production years: 2010-present
Gen4 production began 2010. The G31 Gen4 was the last generation produced for this model as Glock discontinued the .357 SIG lineup.
Origin
Country of origin: Austria
Designer: Gaston Glock
Notes
The G31 Gen4 shares identical external dimensions with the Glock 22 Gen4 (.40 S&W) and can be converted between calibers with a barrel swap, since the .357 SIG is a necked-down .40 S&W case. Weight without magazine is 660g (23.28 oz). The Gen4 dual recoil spring was particularly beneficial for the .357 SIG, as the cartridge's higher operating pressure produces a sharper recoil impulse than .40 S&W. The .357 SIG's bottleneck case design provides extremely reliable feeding. The G31 Gen4 has been discontinued as the .357 SIG market has contracted with many agencies transitioning back to 9mm following the FBI's 2014 ammunition study. Compatible with G22 .40 S&W magazines (same magazine body, different feed lips).
Background
The G31 Gen4 represented the zenith of the .357 SIG's law enforcement era. State police agencies across America -- Virginia, Delaware, Texas, North Carolina -- standardized on the platform, valuing its ability to defeat car windshields and door panels that could stop conventional handgun rounds. The Gen4's modular backstraps were a welcome addition for agencies with diverse officer hand sizes. When the FBI's 2014 study concluded that modern 9mm defensive ammunition had closed the performance gap with larger calibers, the .357 SIG's days as a mainstream law enforcement round were numbered, making the G31 Gen4 the final chapter of an era.