SIG P320 Extended 21-Round Magazine

The SIG Sauer P320 21-round magazine provides four additional rounds over the standard full-size magazine while maintaining factory reliability. The extended base plate adds approximately half an inch to the overall length, creating a full grip for shooters with larger hands while delivering meaningful capacity increase for duty or competition use.

The same steel construction and anti-friction coating used in standard P320 magazines ensures reliable feeding and durability. The extended spring is calibrated to provide consistent tension throughout the capacity range, maintaining the smooth operation expected from factory SIG magazines.

This capacity strikes an excellent balance for practical use - enough extra rounds to matter in competition or defensive scenarios, but not so extended that it compromises handling. Many shooters use the 21-round magazine as their primary carry magazine in full-size P320s, appreciating the additional capacity without significant bulk increase.