The PMAG 30 AR 300 B GEN M3 30rd, 300 Blackout magazine.The PMAG 30 AR 300 B offers a safer way to feed your 300 Blackout rifle. When using 5.56x45mm mags, the potential to chamber and fire a 300 Blackout round in a 5.56x45mm rifle with catastrophic results requires diligent ammunition management by the shooter. The PMAG 30 AR 300 B features aggressive front and rear texture, an easily removable slim floor plate, a paint pen dot matrix for marking and identification Made in the USA.