Engineered specifically for the 300 AAC Blackout, the Magpul PMAG 20 AR 300 B GEN M3 ensures flawless feeding and reliable performance where it matters most. Unlike standard 5.56 mags, this PMAG is tuned for the unique shape of 300 BLK rounds—reducing misfeeds and maximizing reliability.


 


Built from impact-resistant polymer, the PMAG 20 AR 300 delivers Magpul’s legendary toughness in a compact 20-round profile. Perfect for use with suppressed rifles, hunting, defense, or range work, this magazine is lightweight, easy to handle, and built to last.


Key Features 


20-round capacity (300 AAC Blackout only)


Optimized internal geometry for 300 BLK rounds


Durable, impact-resistant polymer construction


Slim, compact 20-round design for prone shooting & storage


Anti-tilt, self-lubricating follower for smooth feeding


Stainless-steel spring resists corrosion


Compatible with AR-15/M4 platforms chambered in 300 BLK


⚠️ Note: Not recommended for 5.56/.223 — designed exclusively for 300 Blackout.