The Glock 21 Gen4 remains one of the most reliable and accurate combat pistols on the market. The adjustable reach and interchangeable backstrap make it attractive to an even wider variety of shooters.
While attending an event at Gunsite Academy in Arizona celebrating the 25th anniversary of Glock, I was given the opportunity to spend a day with the latest generation of Glock 21 pistol—the Gen4. Taking hold of the pistol, the difference was immediately noticeable—even with the standard grip strap.
The real test, however, would be on the range. Drills incorporated some accuracy testing, shooting from prone and at the end of the day we heated things up a bit with a well-rounded test.
The full-size G21 Gen4 provided accuracy and reliability, working perfectly over the course of a hard day on the range for the author. Like all Glock pistols, the G21 Gen4 features a large ejection port and an external extractor. The pistol proved to be 100-percent reliable.
A G21 in its earlier generations spent a couple years in my SWAT rig. As the department armorer and SWAT tactical command at the time, I felt it was a perfect mating for the team. Although budgetary restrictions prevailed, the idea was to equip every SWAT team member with a G21 to go with their HK UMP subgun in .45 ACP. Many teams have taken similar steps, especially if their team is restricted to pistol-caliber entry weapons. The .45 ACP is a proven caliber in these situations whether fired from the shoulder or the hand.
The Glock 21 pistol is really a spin-off of the Glock 20. The Glock 20 was introduced in 1991 to take advantage of the 10mm round. In order to handle the cartridge it needed a larger frame, slide, and magazine. The Glock 20 was marketed primarily as a pistol for military and security forces, with some attention as a potential hunting pistol. The 10mm was pretty popular at the time and the Glock seemed a perfect mating. With a 15-round magazine, it provided significant firepower and capacity in a controllable and rugged pistol. For all its ballistic advantage, the 10mm was hard for many to shoot. The .45 ACP was, and remains one of the most popular working pistol calibers in America. Many agencies preferred that caliber as the .40 S&W had yet to be proven. In order to capitalize on that market, the Glock 21 was developed. It utilized a 13-round magazine and some changes to the slide to handle the difference in pressure. The grip was just a tad larger, but overall it was very similar in size.