Built to hold (30) rounds of ammunition. Will only hold 300 AAC Blackout rounds. Constructed of next-generation impact and crush resistant polymer. This magazine also comes equipped with a hi-tensile compression steel spring to assure this magazine has minimal to no friction, and smooth feeding responses. The GEN M3 Window incorporates new material technology and manufacturing processes for enhanced strength, durability, and reliability to exceed rigorous military performance specifications.

The PMAG® 30 AR 300 B GEN M3™ is a purpose-designed magazine for rifles chambered in 300 Blackout®. Since its inception, 300 Blackout shooters have had to use a magazine designed for another cartridge, limiting its ultimate performance and compatibility. One of the nice features of 300 Blackout is the compatibility with 5.56x45mm parts, but with the magazine it is a compromise to do so. Due to the wide variety of projectile weights and profiles potentially decreasing overall reliability, a dedicated 300 Blackout magazine was a logical step for the PMAG line.