The Mossberg 590 Shockwave is a 14-inch barreled firearm classified by the ATF as a Firearm rather than a shotgun or SBS because it was never configured with a stock, making it legal in most states without NFA paperwork. The Shockwave grip replaces the traditional stock. Type: Shotgun Action: Pump-Action Caliber: 12 Gauge Capacity: 6 Year introduced: 2017, USA Weight: 5.25 oz Overall length: 26.37" Status: Active Intended use: Home Defense/Novelty