Magpul PMAG 300 B Gen M3 Black AR15 300 AAC Blackout Rifle Magazine - 20 Rounds - The PMAG 20 AR 300 B GEN M3 is a purpose-built magazine for rifles chambered in .300 Blackout (300 BLK). Similar in every way to Magpul's PMAG 30 AR 300 B, the PMAG 20 is more compact for increased maneuverability and creates a more concealable package for use in small format firearms. Since its inception, 300 BLK shooters have had to use a magazine designed for another cartridge, limiting that round's ultimate performance and compatibility. One of the key features of 300 BLK in the past has been its compatibility with 5.56x45mm magazines. However, even with moderate success with that particular magazine, it is a compromise to do so, with reliability and safety both being at risk. In addition to the performance gained by a dedicated mag, the PMAG 20 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 20 AR 300 B's distinct ribbed 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 BLK performance, the PMAG 20 incorporates all of Magpul's GEN M3 features, including their next-generation impact and crush resistant polymer, aggressive front and rear texture, an easily removable slim floor plate, a paint pen dot matrix for marking and identification, and a dust/impact cover. Purpose-Built Magazine Only For 300 BLK Designed With Visual And Tactile Differences Incorporates The Same Features And Performance Of The Gen M3 Line Made In The USA