Mossberg introduced the 590 Shockwave 12-gauge pump firearm in 2017, and a variety of different shotgun manufactures copied the idea and created their own version of these guns that are classified as firearms, and not shotguns, by the ATF. Recently, Mossberg applied the Shockwave treatment to a semi-auto firearm and called it the 990 AfterShock. Citadel, a brand by Legacy Sports International, has a version of the original 590 Shockwave and calls it the Tidalwave. We wanted to revisit these firearms — humor us as we call them shotguns going forward — and take a look at the difference between semi-auto actions versus pump actions, covering the operational differences well as tactical differences. We found there are many pros and cons with these types of firearms.
