SIG SAUER P365 High-Capacity Micro-Compact Pistol This revolutionary striker-fired 9mm pistol offers the perfect balance of capacity and concealment with unrivaled shootability and ergonomics. The P365’s patent-pending, narrow-neck, modified double-stack magazine holds 10 rounds in both the flush-fit and extended versions, plus one in the chamber, for a full capacity of 11 rounds – nearly a 50 percent capacity increase over pistols in its class.