Is this the MOST Compact SUB GUN? - The SIG MPX Copperhead

Is this the MOST Compact SUB GUN? - The SIG MPX Copperhead Details: The MPX Copperhead features a monolithic Elite Series Cerakote® finish upper receiver, with an integrated stock knuckle lower, and a 3.5” barrel with integrated muzzle brake. The MPX Copperhead comes equipped with the new SIG SAUER Pivoting Contour Brace (PCB) giving pistol users a brace that easily adapts to the movement of the shooter’s arm with a patented swivel operation for perfect placement, and can be rapidly deployed. Unconventional design, unmatched performance, and familiar AR handling. The SIG MPX redefines the submachine gun category with a new level of operator safety, in-field adaptability and proven reliability in the harshest environments. Completely ambidextrous, the SIG MPX is great for left- or right-handed shooters with its dual-sided selector switch, magazine release, charging handle and bolt release. The SIG MPX operates from a fully-closed and locked rotating bolt, offering enhanced reliability and safety in use. A s