The SIG Sauer MCX Virtus is the modular variant of the MCX platform chambered in 5.56 NATO. The Virtus adds a fully ambidextrous lower receiver, a quick-detach barrel system allowing caliber swaps between 5.56, .300 BLK, and 7.62x39mm, and a folding stock. The short-stroke piston operates independently of the stock — the Virtus can fire with the stock folded. Type: Rifle Action: Semi-Automatic Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 2017, USA Weight: 128 oz Overall length: 35" Status: Active Intended use: military, law_enforcement, tactical, sporting