HANDGUN UNBOXING US Military unboxing the powerful Sig Sauer P320 M17 Handgun great for self defense
The SIG Sauer P320 is a semi-automatic pistol made by SIG Sauer of Exeter, New Hampshire and SIG Sauer of Eckernförde, Germany. The SIG Sauer P320 can be chambered in 9×19mm Parabellum, .357 SIG, .40 S&W, and .45 ACP. The P320 chambered in 9×19mm Parabellum was introduced in the North American market on January 15, 2014 followed by the .45 ACP compact model at the SHOT Show in January 2015. The P320 is a further development of the SIG Sauer P250 utilizing a striker-fired mechanism in lieu of a double action only hammer system. On January 19, 2017, it was announced that the SIG Sauer P320 had won the United States Military XM17 Modular Handgun System competition, with a specialized version to become the new M17 pistol.
Like other SIG Sauer pistols, the P320 pistol is a short recoil operated, locked breech pistol. It uses the typical SIG Sauer cam-operated barrel, which locks into the ejection port on the slide.
A key feature of the pistol is its modular design. The main module of the P320 is an internal stainless steel frame fire control unit, which consists of the integrated fire control group (trigger, and all necessary linkage and springs), ambidextrous slide release (one on each side of the pistol), ejector and four slide rails. This steel receiver unit is used in every P320 grip module, top end, and chambering combination and is inserted into the grip frame module and held in place by the axis pin of the disassembly lever. The firearm's serial number is on the fire control unit instead of the grip module. The fire control unit allows the operator to interchange differently-sized slide assembly or top end modules and polymer grip frame modules and trigger shoes and (limited) chambering conversions to adapt the gun to the individual user and address different needs.
The P320 was designed to be ambidextrous in handling, sporting an ambidextrous slide catch lever and user reversible magazine catch. All other operating controls are designed so they can be operated from either side. The firearm can be field stripped with no tools. Additionally, the firearm can also be field stripped without depressing the trigger, an additional safety feature to prevent negligent discharge of the weapon.
The full-size, carry and compact grip modules feature an integral Picatinny rail mounting-bracket at the lower forward edge of the module to allow the mounting of laser sights, tactical lights, and other accessories.
The P320 pistol is offered in three Glass-filled polymer grip module sizes—small, medium, and large—in each of the full-sized, carry, compact, and subcompact P320 variants. The pistol top ends also come in full-sized, compact, and subcompact variants that will fit the correspondingly sized grip modules. Every chambering can be converted by the user with a caliber exchange kit. The 9×19mm Parabellum, .40 S&W, and .357 SIG chamberings share their polymer grip frame modules and this offers the possibility to interchange these three chamberings by swapping the top end—consisting of the slide, recoil spring assembly, barrel and the box magazine. Due to the significantly larger external dimensions of the .45 ACP cartridge compared to the other P320 chambering options, the .45 ACP chambering uses slightly wider .45 ACP–specific polymer grip modules with an enlarged magazine well. The firearm's "fire control group", which contains the only serialized part of the firearm, is also slightly different to accommodate the enlarged magazine well.
The manufacturer offers caliber exchange kits or Caliber X-Change kits consisting of a slide, recoil assembly, barrel, box magazine and grip module in the varying frame sizes, grip module sizes and chambering variants in which the P320 pistol is offered. These kits enable a user to switch between the various P320 configurations without the use of tools.
The standard P320 has no manual safeties, promoting instant readiness. Instead of manual safeties, an automated firing pin safety ensures safe carrying of the weapon, while preventing accidental discharges if the gun is dropped or roughly handled. The Modular Handgun System (MHS) or M17 version of the P320 has an ambidextrous thumb safety.
The trigger is a pretensioned striker DAO trigger system. The trigger system has a pull weight of about 28.95 N, 5.5 lbf 
The P320 trigger is available in standard (solid) and tabbed (with trigger safety).
The P320 is available with a 120 mm (4.7 in), 98 mm (3.9 in), or 91 mm (3.6 in) barrel depending on the size (full-sized, carry/compact or sub-compact respectively).
The pistol feeds from metal detachable box magazines with a six- to twenty-one-round magazine capacity, depending on chambering and pistol size.
The P320 comes with three-dot combat-type iron sights of which the front sight element can be drifted to