Like the company's original Shockwave design, the receiver and heavy-walled, cylinder-bore barrel on the 590 Nightstick are borrowed from the company's heavy-duty Model 590 shotgun, the same design employed by many military and law-enforcement units. However, in lieu of the polymer fore-end, Raptor grip and synthetic strap, Mossberg added a ribbed, wooden fore-end, a wooden Raptor grip complete with sling-swivel mount and a leather strap that keeps a shooter's support hand secured firmly to the forearm.
Each Mossberg 590 Nightstick measures 26.37 inches long and weighs in at 5.25 pounds, unloaded. The barrel measures 14.375 inches in overall length and is topped with a brass-bead front sight. Like Mossberg's 500 and 590 series of shotguns, the 590 Nightstick features a tang-mounted sliding safety and a bolt-release lever located on the left-hand side of the trigger guard. The aluminum receiver is treated with a black, hard-anodized finish, and the barrel and magazine tube are also coated with a color-matching, matte-black finish. The 590 Nightstick's chamber can accommodate 12-gauge shotshell lengths of up to 3 inches, and the magazine tube can hold five 2.75-inch shotshells. The suggested retail price on the Mossberg 590 Nightstick is $539.