The PMAG 30 AR 300 B also offers a safer way to feed your 300 BLK rifle. When using 5.56x45mm mags, the potential to chamber and fire a 300 BLK round in a 5.56x45mm rifle with catastrophic results requires diligent ammunition management by the shooter. The PMAG 30 AR 300 Bs distinct rib design and smoother upper-half texture provides the shooter a distinct visual and tactile difference from any other PMAG to mitigate dangerous cross-loading issues. Along with optimized 300 Blackout performance, the PMAG 30 AR 300 B incorporates all of the GEN M3 features such as our next-generation impact and crush resistant polymer, aggressive front and rear texture, an easily removable slim floor plate, and a paint pen dot matrix for marking and identification.