SHOTGUN: JTS FIREARMS MODEL M12AR, SERIAL NUMBER MR18000115, BLACK (MATTE), YES - INCLUDES PROTECTIVE CASE, 20", 12 GAUGE, SEMI - AUTOMATIC Notes: The M12AR incorporates familiar AR-style controls and a Picatinny optics rail, along with an aluminum M-LOK-compatible forearm for accessory mounting. Manufacturer: JTS Group / JTS Firearms Model: M12AR Type: Semi-automatic, magazine-fed shotgun Gauge: 12 gauge Chamber: 2 3/4-inch and 3-inch shotshells Operating system: Gas-operated semi-automatic action with a four-position adjustable gas system, intended to accommodate different loads.