Magpul recently introduced the PMAG 20 AR 300 B Gen M3, a purpose-built magazine designed for the .300 BLK. Although it is similar to the PMAG 30 AR 300 B, the new variant is said to be more maneuverable thanks to a more compact construction that is more concealable and pairs nicely with small-format firearms.
Fans of the .300 BLK have long had to use magazines designed for another cartridge, which limits compatibility and overall performance. What Magpul set out to do with the new PMAG 20 AR 300 B Gen M3 was build a .300 BLK magazine specifically for the varied projectile weights and profiles of the cartridge.
To help shooters avoid the problem of inserting a 5.56 mag into a .300 BLK firearm, Magpul designed the new magazine with distinct ribbing and a smoother upper half texture to provide shooters with a distinct visual and tactile difference from any other PMAG. This is said to help prevent cross-loading and the catastrophic results that could follow.
The new Gen M3 mag is also said to aid in the performance department, thanks to impact- and crush-resistant polymer, aggressive front and rear texturing, a slim floor plate, paint pen dot matrix for identification marking, and a dust/impact cover.
Optimized for maximum reliability using 300 BLK ammunition
Utilizes all PMAG Gen M3 556/300B compatible accessories
Unique rib design to provide instant differentiation from 5.56 mags in all conditions
Compatible with STANAG mag well rifles chambered in .300 BLK