Magpul PMAG Gen M3 300Blk 20 Round Magazine

The Magpul PMAG 300B GEN M3 is a purpose-built magazine specifically designed for rifles chambered in .300 Blackout (300 BLK). Unlike traditional 5.56×45mm magazines, which many 300 BLK shooters have historically used with mixed results, the PMAG 300B eliminates compatibility issues and enhances both performance and safety. Using a 5.56 magazine with 300 BLK can result in feeding issues and, more seriously, the risk of chambering a 300 BLK round into a 5.56 rifle potentially causing catastrophic failure. The PMAG 300B GEN M3 addresses this with a distinct ribbed texture and a smoother upper half for clear visual and tactile differentiation, helping prevent dangerous cross-loading mistakes. Engineered with all the latest GEN M3 features, this magazine includes impact- and crush-resistant polymer construction, aggressive front and rear texturing for improved handling, a slim, tool-less removable floorplate, and a paint pen dot matrix for marking and easy identification.

The constant-curve internal geometry and anti-tilt follower ensure reliable feeding, while the stainless steel spring offers long-term durability. The compact PMAG 20 AR 300 B is ideal for small-format firearms and increased maneuverability, while the full-capacity PMAG 30 AR 300 B is perfect for standard-length setups. Both deliver smooth cycling, consistent performance, and enhanced safety in any environment. Whether you're building a dedicated .300 Blackout rifle or upgrading your magazine loadout, the Magpul PMAG 300B GEN M3 offers unmatched reliability, optimized performance, and purpose-driven design.

FEATURES

• Purpose-built magazine only for 300 BLK
• Dedicated, reliable magazine for rifles chambered in 300 BLK that supports the differing geometries found in that caliber
• 20-round body is more compact for increased maneuverability, creating a more concealable package for use in small format firearms
• Distinct rib design and texture provide visual and tactile differentiation from other PMAGs to mitigate dangerous cross-loading issues
• Incorporates the same features and performance of the Gen 3 line
• Next-generation impact and crush-resistant polymer, aggressive front and rear texture, easily removable slim floor plate, a paint pen dot matrix and an impact/dust cover

SPECIFICATIONS

• Manufacturer: Magpul
• Model: PMAG 300B GEN M3 300BLK 20Rd Magazine
• MPN: MAG1182-BLK
• UPC: 840815132233
• Caliber/Gauge: 300 Blackout
• Capacity: 20
• Fits Make & Model: AR15, M4, M16, FN SCAR, IWI Tavor
• Material: Impact and crush resistant polymer
• Weight: 4.86 oz
• Base Plate: Flat
• Magazine Finish: Black

WHAT'S IN THE BOX

• Magpul PMAG 300B Gen M3 300Blk 20 Round Magazine