MBX Extreme PCC magazines deliver competition-focused reliability in high-capacity form factors for USPSA PCC and 3-Gun carbine shooters. Designed around consistent feed-lip geometry and spring tension calibrated for the blowback and delayed-blowback cycle rates of competition carbines, these magazines load smoothly, drop free reliably, and stand up to repeated stage drops. Available in multiple capacities to match match-legal round count requirements. Fast same-day shipping on most orders at Shooters Connection.