The Bureau of Alcohol, Tobacco, Firearms & Explosives has confirmed the 590 Shockwave as a firearm per the Gun Control Act (GCA) but it is not a Class 3/NFA firearm. Some listed items may not be legal in every state. Stay Tuned to the RE Factor Tactical Blog and be part of this all VETERAN-run website. The Mossberg Shockwave is a Mossberg 590 with a shortened barrel and the famous Raptor Birds Head style pistol grip, instead of a shoulder stock. Checking out the @mossbergcorp Shockwave Boomkit from @brownellsinc today.