Glock G21 Magazine Features The Glock Factory Handgun Magazine is purpose built for the G21 pistol in .45 ACP holding 10 rounds of ammunition in a black polymer body. An orange follower at the top of the magazine provides a quick visual cue when the magazine is empty or nearing empty useful during range sessions or training drills. Being a genuine Glock factory magazine it is manufactured to the exact tolerances used in original equipment ensuring reliable feeding and proper fit in the G21 frame. That consistency matters for shooters who rely on their magazines functioning the same way every time. Glock magazines like this one can be difficult to load fully when brand new and the last round may not seat easily until the magazine has gone through a break-in period. Loading the magazine with all but the final round and letting it sit for a few days helps compress the spring and ease future loading. Cycling the magazine from full to empty several times can also help speed up this break-in process. For G21 owners looking for a dependable factory spare or replacement magazine this Glock magazine is available for sale at GrabAGun. Glock G21 Magazine Specifications Manufacturer: Glock Model: Magazine for G21 Caliber: .45 ACP Capacity: 10 Rounds Finish: Black Polymer Follower: Orange Available At: GrabAGun