

Brown triggers, levers and catches were used only early in production. The XM17 prototype with 17-round magazine inserted. Every M17/M18 handgun is test fired before leaving the factory with 13 rounds - three to break in the weapon and ten to test accuracy. The Modular Handgun System has self-illuminating tritium sights for low-light conditions, an integrated rail for attaching enablers and an Army standard suppressor conversion kit for attaching an acoustic/flash suppressor. Using spanner screws instead of normal screws to resist disassembly further than field stripping by non- armorer users.Steel components are given a physical vapor deposition (PVD) corrosion-resistant finish.A 17-round standard magazine, with an optional 21-round extended magazine available.Chambered in 9mm NATO unable to adopt other calibers or frames because of the spanner screw on the frame's chassis.98 mm (3.9 in) barrel length in carry-size M18.120 mm (4.7 in) barrel length in full-size M17.Improved trigger "mud flap" to prevent foreign debris from entering the pistol action.Improved slide sub-assembly to capture small components when disassembled.Slide cut out to facilitate the addition of a reflex sight this is the slide from the RX Series.SIG Sauer submitted a P320 with a number of modifications for the XM17 Modular Handgun System competition. Army, one of the tenets of the proposal was that an existing model handgun was desired to fulfill the requirements laid out in the Modular Handgun System Request for Proposal, known as the XM17 Procurement. When the requirements were formulated for a new handgun for the U.S. Standard issue M18 with 17-round magazine inserted There are two color variants, coyote brown and black, for both the M17 and M18, though almost all have been produced in brown. The pistol replaces the Beretta M9, as well as several other handguns across the services. The guns have subsequently been adopted by the Army, Navy, Marine Corps, Air Force, and Space Force. The full-sized model was designated the M17, and the shorter length carry model, the M18.

On January 19, 2017, the United States Army announced that a customized version of SIG Sauer's P320 had won the Army's XM17 Modular Handgun System competition. The SIG Sauer M17 and M18 are service pistols derived from the SIG Sauer P320 in use with the United States Armed Forces. Self-illuminating iron sights for low-light conditions SIG Sauer, Inc., Newington, New Hampshire, U.S. Standard issue M17 with 21-round magazine inserted
