Glock 21 Gen4
Glock Ges.m.b.H. · Pistol · In Production · 2012
Also known as: G21 Gen4, Glock 21 SF
Overview
The Glock 21 Gen4 is the fourth-generation full-size .45 ACP service pistol from Glock, delivering the stopping power of the .45 Auto round in a polymer-framed, striker-fired platform with a standard 13-round magazine capacity. The Glock 21 was originally introduced in 1990 as Glock's answer to American demand for a .45 ACP pistol, built on a modified Glock 20 (10mm Auto) frame to accommodate the wider .45 cartridge. The Gen4 variant, released in 2012, introduced the modular backstrap system with three interchangeable grip sizes, a dual recoil spring assembly with steel support for reduced felt recoil and extended service life, an enlarged reversible magazine catch, and a more aggressive rough-textured frame. Its octagonal polygonal rifled barrel provides improved accuracy and higher muzzle velocity compared to conventional land-and-groove barrels, while the Safe Action trigger system with three independent passive safeties ensures reliable and safe operation. The Glock 21 remains popular with law enforcement agencies and civilian shooters who prefer the proven .45 ACP cartridge in a high-capacity, lightweight, and reliable modern handgun.
Specifications
| Weight (empty) | 745 g (26.3 oz) |
| Weight (loaded) | 1100 g (38.8 oz) |
| Overall Length | 205 mm (8.07") |
| Barrel Length | 117 mm (4.61") |
| Height | 140 mm (5.51") |
| Width | 34 mm (1.34") |
| Sight Radius | 172 mm (6.77") |
| Action Type | Short Recoil |
| Firing Mechanism | Striker Fired |
| Trigger Type | Safe Action |
| Trigger Pull | 28 N (6.3 lbf) |
| Magazine Capacity | 13 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 253 m/s (830 fps) |
| Muzzle Energy | 477 J (352 ft·lbf) |
| Effective Range | 50 m (55 yd) |
| Maximum Range | 1500 m (1640 yd) |
| Barrel Rifling | Polygonal |
| Rifling Twist | 400 mm (15.75") |
| Number of Grooves | 8 |
| Frame Material | Polymer |
| Slide Material | Steel |
| Barrel Material | Steel |
| Finish | Gas Nitride |
Calibers
- .45 ACP · primary — also known as .45 Auto, 45 Auto, 11.43x23mm
Features
- Firing modes: Semi Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Trigger Safety, Firing Pin Safety, Drop Safety
- Features: Modular Backstrap System, Reversible Mag Release, Dual Recoil Spring, Accessory Rail, Rough Textured Frame, Finger Grooves
Variants
- Glock 21 Gen5 MOS — Optics Ready
- Glock 21 SF — Short Frame
- Glock 21C — Compensated
- Glock 30 Gen4 — Subcompact
Service history
Operators
- Hellenic Armed Forces
- United States Special Operations Command
- Various U.S. Law Enforcement Agencies
Production
Production years: 2012-present
Gen4 specific production unknown. The Glock 21 was first introduced in 1990. Total Glock production across all models exceeds 20 million.
Origin
Country of origin: Austria
Designer: Gaston Glock
Notes
The Glock 21 was the first .45 ACP pistol ever produced by Glock, introduced in 1990 alongside the Glock 20 (10mm Auto). Notably, there was no Gen1 Glock 21 -- all original 1990 models were Gen2 pistols, as the Gen1 era (1982-1989) predated the model's existence. The Gen4 dual recoil spring assembly replaced the Gen3's single captive spring, reducing felt recoil by approximately 20% and extending the spring's service life. Weight with empty magazine inserted is 830g. The slide width is 28.5mm (narrower than the 34mm overall frame width). Standard magazine capacity is 13 rounds with optional 10-round magazines available. The Gen4's modular backstrap system includes standard, small, and large grip inserts. The Glock 21 Gen4 has been superseded by the Gen5 MOS variant which adds the Glock Marksman Barrel, nDLC finish, flared magazine well, and optics-ready slide cuts.
Background
The Glock 21 was Glock's first .45 ACP pistol, introduced in 1990 alongside the Glock 20 (10mm Auto). There was never a Gen1 Glock 21 -- the model postdates the Gen1 era entirely, making all original 1990 examples Gen2 pistols from the start.