In recent years, the pistol-caliber carbine concept has taken off like wildfire, since shooters can take advantage of lower recoil and more affordable ammunition to enhance their range experience and personal-defense training setup. Now, This Glock-Style Drum Magazine gives owners of 9mm PCCs an incredible magazine capacity, holding up to 50 rounds. Each Glock-Style 9mm Drum Magazine is constructed for use in all Glock®magazine-compatible ARs on the market, which are some of today's most-popular PCCs. Due to the unique design of this drum magazine, it's only compatible with AR-style magazine wells and will not work in Glock®pistols. This Lock-Style 9mm Drum Magazine is made from durable Zytel-based polymer, and the upper tower of the magazine features a full-length steel insert that's stamped and welded just like an OEM Glock®magazine. The mag also features a spring made from heat-treated stainless steel, and the unit uses an injection-molded magazine follower.