Magpul PMAG 20 AR 300 B Gen M3 Rifle Magazine 300 AAC BLK 20/rd

The Magpul PMAG 20 AR 300 B Gen M3 rifle magazine is a purpose-built 20-round magazine specifically engineered for .300 AAC Blackout (300 BLK) platforms. Unlike earlier designs that forced operators to adapt magazines designed for other cartridges, this Gen M3 magazine delivers full optimization for the 300 Blackout round, ensuring reliable feeding and extraction without compromise.

The 20-round capacity strikes a practical balance for intermediate-range work and CQB applications. Compared to the PMAG 30 AR 300 B, the reduced capacity translates to a more compact, lower-profile package that enhances maneuverability in confined spaces and improves concealment in small-format rifles and short-barreled configurations. The magazine maintains Magpul's proven reliability standards with reinforced feed lips, anti-tilt followers, and witness holes for quick capacity verification during tactical reloads or inventory checks.

This magazine suits patrol carbines, specialty law enforcement builds, and dedicated 300 Blackout precision platforms where the round's subsonic ballistics and reduced recoil impulse demand matched ammunition and magazine geometry. The design is compatible with standard AR-platform lower receivers chambered in 300 BLK. Field operators and competition shooters deploying 300 Blackout ammunition benefit from the elimination of cross-caliber feed issues that plagued previous workarounds. The compact footprint makes this an essential upgrade for anyone running 300 BLK in tight operational or training environments.