Mossberg 51665: These Mossberg 590A1\'s are built to demanding military and law enforcement specs. Now civilians can get the same rock-solid 590A1 shotguns that have proven themselves in duty applications worldwide for decades. 590A1 models are built for the most demanding on-duty conditions, with Parkerized heavy-walled barrels, metal trigger guards and safety buttons standard on all models. Inside, they feature dual extractors, twin action bars, positive steel-to-steel lock-up, and an anti-jam elevator combined for reliable, smooth operation. Offered in 12 gauge, the 590A1 chambers 2.75\" and 3\" factory shotshells. All receivers are drilled and tapped, ready for Picatinny rail, sight or optics installation. This Retrograde model features a heavey-walled barrel with a heatshield, ghost ring sights, and a walnut stock.