Mossberg 590A1 Retrograde is a rugged, combat-proven 12-gauge shotgun. It has a 20-inch, heavy-walled cylinder-bore barrel that is capable of firing 2¾- or 3-inch shells. The 590A1 has a corrosion-resistant Parkerized finish with a total capacity of nine rounds (8+1). It features dual extractors, positive steel-to-steel lockup, twin action bars, and an anti-jam elevator that ensures smooth operation.