Strike Industries Extended Magazine Plate, Fits Sig P320 Magazine, +5 Capacity, Black SI-EMP-P320 The Strike Industries Extended Magazine Plate For SIG SAUER P320 (9mm) was designed to provide smoother magazine reloading through a slow drag / no snag design while maintaining maximum magazine capacity. The Extended Magazine Plate (EMP) adds plus 5 rounds (9mm) to P320 magazines.