The MPX Copperhead is the most compact MPX variant, featuring a 3.5-inch barrel with a folding Tailhook brace in pistol configuration, combining the piston-operated MPX platform in the smallest possible suppressor-host format. Type: Semi-Auto Pistol Action: Gas-Operated Caliber: 9mm Capacity: 20 Year introduced: 2019, USA Weight: 4.5 oz Overall length: 17.3" Status: Active Intended use: Suppressor Host, NFA/SBR, Tactical, PDW, Home Defense