Magpul PMAG 20 AR 300 Gen M3 300 Black MAG1182BLK

The PMAG 20 AR 300 B GEN M3 is a compact, purpose-built magazine designed specifically for rifles chambered in .300 Blackout, giving shooters a dedicated solution that finally matches the cartridge’s true potential. While its larger sibling, the PMAG 30 AR 300 B, delivers the same performance in a higher-capacity format, the 20-round version excels when maneuverability, balance, and concealability matter most. Its shorter profile is ideal for small-format firearms, tight shooting positions, and practical defensive setups where a full-length magazine may get in the way.

For years, .300 BLK shooters relied on magazines intended for 5.56x45mm, accepting compromises in reliability, consistency, and safety. The PMAG 20 AR 300 B breaks from that limitation with internal geometry engineered expressly for the broader profile and unique feed characteristics of .300 Blackout. From supersonic loads to heavy subsonics, this magazine enhances feeding performance across the board, giving shooters the dependable function they’ve been asking for.

Safety is another major improvement. Mixing .300 BLK and 5.56 magazines can lead to catastrophic errors, as a .300 BLK round can chamber in a 5.56 rifle. Magpul solved this by giving the PMAG 20 AR 300 B a distinct rib pattern and a noticeably smoother upper texture, creating an unmistakable tactile and visual difference from any standard PMAG. This reduces the risk of cross-loading and reinforces good ammunition management without slowing the shooter down.

Built with the full suite of GEN M3 refinements, this magazine uses an advanced impact- and crush-resistant polymer that handles hard use, rough environments, and long-term storage without complaint. Aggressive front and rear texture ensures a secure grip during reloads, while the slim, easily removable floorplate keeps maintenance simple. Magpul’s paint pen dot matrix adds space for clear identification, making it easy to label magazines for specific loads or rifles.

Like every Magpul polymer magazine, the PMAG 20 AR 300 B GEN M3 is proudly made in the USA, delivering the workmanship, reliability, and rugged performance shooters expect from American manufacturing.

Order it today from SMKW!