ProMag DRMA37 Standard 45 ACP 40-Rd Drum Magazine for Glock 21/30 Black Polymer

The ProMag DRMA37 is a high-capacity 40-round drum magazine built for .45 ACP Glock 21 and Glock 30 pistols. The drum format dramatically extends the firepower of a standard Glock duty or carry pistol, making it a natural fit for range sessions, competition shooting, and high-round-count training drills where constant reloading slows you down.

The drum housing is molded from a proprietary DuPont Zytel polymer in black, giving the magazine a lightweight yet impact-resistant body that matches the look of factory Glock magazines. Internally, the DRMA37 uses a magazine spring and an injection-molded follower for smooth, consistent feeding. The drum installs into the Glock magwell like a standard double-stack box magazine, so no pistol modification is required.

ProMag is an established aftermarket magazine maker, and the DRMA37 gives Glock 21 and Glock 30 owners a dependable 40-round drum option in .45 ACP.