The Magpul PMAG 30 AR 300 Blackout GEN M3 Magazine is purpose-built for rifles chambered in 300 Blackout. While 300 BLK is compatible with 5.56x45mm parts, having a dedicated 300 Blackout PMAG significantly improves overall reliability. This 300 BLK mag is built with next-generation crush-resistant polymer with aggressive front and rear texture for easy handling. Plus, the Magpul 300 Blackout magazine has a distinct ribbing and smooth upper half for a clear visual and tactical difference from other PMAGs, significantly reducing the chance of cross-loading. Improve the reliability of your 300 Blackout rifle with the purpose-designed Magpul PMAG 30 AR 300 Blackout GEN M3 Magazine.