guards, and will stand up to harder use. In 2018, Mossberg released the 590M, a pump-action shotgun fed by a double-stack magazine. It is available in three models; one is a derivative of the Shockwave, the other two are variants of the base 590, one having ghost ring sights and a heat shield, the other without. The magazines are available in 5, 10, 15, and 20-round capacities. Law enforcement models Mossberg shotguns currently designated "law enforcement models" are 590A1s. 590A1s differ from other 500/590 shotguns, in that they have heavy barrels, metal trigger guards, and metal safeties. 590A1s are available in , , and barrels. The 590A1 is also used by the U.S. and allied armed forces, having been designed to meet the stricter standards outlined by the U.S. Army. Model 500s were also previously sold as law enforcement combos in 12 gauge with both and barrels, birch buttstock, pistol grip and sling. Home security model The model 500 HS410, or "Home Security" model, is available in .410 gauge only, and is specifically designed for defensive use. It comes with a youth-sized stock, a vertical foregrip, and a special muzzle brake and spreader choke (to help produce wider patterns when using buckshot) on an bead sight barrel. The .410 gauge round, while by far the least powerful common shotgun chambering, remains a formidable shotgun shell. A 90-grain slug generates energy close to (and in some manufacturer claims, exceeding) a .357 Magnum when fired from a full length barrel. The HS410 is targeted at the novice user who desires a simple, easy to use, and effective defensive weapon. It is packaged with an introductory video covering use and safety, and some versions have a laser sight mounted in the foregrip. Mossberg Shockwave The Mossberg Shockwave is a pump action firearm based on the 590 series of shotguns. It is distinguished from the rest of the 590 series by its barrel and "birds-head" style grip. The Mossberg Shockwave was the best-selling pump action shotgun in the United States in 2020. Design The action of the Shockwave is taken from Mossberg's 590 series of shotguns. It features the same sliding tang safety on the top rear of the receiver, twin action bars, and dual extractors seen on other models. The name is inherited from the manufacturer of the grip, Shockwave Technologies. Mossberg claims the grip reduces recoil. The Shockwave weighs empty, holds five