SIG Sauer MPX

The SIG Sauer MPX is a gas-operated submachine gun primarily chambered in 9×19mm rounds. It is the first submachine gun to feature a fully closed and rotating bolt system, This is to enhance the safety of the user. It was designed in 2013 and released to the general public in 2015. It features a SIG Sauer short stroke push-rod gas system to reduce recoil and improve the reliability of the weapon. The weapon features a system that allows for conversion from 9mm to .357SIG or .40S&W.

Design details
The standard version of the MPX is the 9mm 8.0 inch (20.3 cm) version with a collapsible stock and free-floating rail. Its overall length is 22.8 inches (58 cm) with the collapsible stock extended and with the standard 8.0 inch barrel. On initial release, these were supplied with a 6.5 inch (16.8 cm) barrel.

Features
The standard MPX submachine gun comes with a rear and front flip-up sight that is attached to the integrated rail system on the top of the weapon. One available modification is a SIG reflex sight mounted to the rail instead of the flip-up sights.

The MPX has a gas short stroke pushrod system in order to increase the accuracy of the weapon which operates in closed bolt. It is designed in this way also to prevent water or dirt from entering the chamber and causing malfunctions. It features an ambidextrous selector switch for fully automatic (law enforcement/military models) and semi-automatic. It also features an ambidextrous bolt catch, and the weapons exterior appears to be a cross between an AR-15 and a Heckler & Koch MP5A3. The barrel is free-floating and is surrounded by Polymer/Steel Rail mounts.

The charging handle of the weapon is based on the M16/AR-15 design at the back of the weapon. This is to ensure that cocking the weapon does not interfere with any optics mounted onto the Picatinny rail. The weapon's rails are made out of cast steel and the standard weapon overall weighs 2.1 kg. The semi-automatic version of the weapon can be registered as a Short-Barreled Rifle in some states in the U.S.

Variants list
MPX (Standard variant) The standard submachinegun complete with a folding stock or a 3 position collapsible stock, 3 position fire selector and 8.0 inch barrel.

MPX-K (Compact variant) The submachinegun with a 4.5 inch barrel.

MPX-P (Pistol variant) The semi-automatic version with no stock and a 8.0 inch barrel.

MPX-PSB (Pistol variant) The semi-automatic version with a pistol stabilizing brace and a 8.0 inch barrel.

MPX-SD (Integrally Suppressed Variant) Standard Submachinegun with an MP5SD like Integral Suppressor and longer-fore-end. Barrel is 8.0 inches.

MPX-C (Carbine Variant) This version is a Semi-automatic Carbine version with a 6.5 Inch barrel and a built-in compensator. It also features a longer fore-end. Sales of this variant were put on hold pending a dispute with ATF over the classification of the barrel.