The SIG Sauer P320 series is a highly versatile modular semi-automatic pistol renowned for its adaptability and modern design. Developed by SIG Sauer, Inc., the P320 is an evolution of the P250, incorporating a striker-fired mechanism instead of the double-action-only hammer system. This pistol is available in multiple calibers including 9×19mm Parabellum, .357 SIG, .40 S&W, .45 ACP, and 10mm Auto. Its modular design allows for easy caliber conversion; changing from .357 SIG to .40 S&W requires only a barrel swap, while switching between 9mm and .357 SIG or .40 S&W is achieved with a caliber exchange kit. Introduced in North America in January 2014, the P320 was selected as the U.S. Army's XM17 Modular Handgun System, known in military service as the M17 (full-size) and M18 (compact). The P320 is distinguished by its ambidextrous design, featuring controls and a catch lever on both sides, as well as a tool-free field stripping process that does not require trigger depression. The firearm's fire control unit is removable, allowing users to switch frames as needed. Variants such as the P320 X-Carry and P320 XFive Legion offer enhanced features including extended magazine capacities, improved grip modules, and optic readiness. The P320MAX, designed for competition, includes a tungsten-infused grip, match-grade barrel, and advanced sights. The P320 AXG (Alloy XSeries Grip) combines an aluminum frame with the P320’s modular system, offering enhanced durability and a premium feel. The P320 Compact variant strikes a balance between size and capacity, making it a versatile choice for both everyday carry and duty use. The P320’s modularity, reliability, and wide range of configurations make it a popular choice among law enforcement and military personnel.