15-22

The Smith & Wesson M&P15-22 is a .22 LR variant of the Smith & Wesson M&P15. In contrast to the original AR-15, it is blowback-operated, rather than direct impingement-operated. It is intended for recreational shooting ("plinking") and hunting. It is made with a polymer upper and lower receiver, rather than the aluminum that is normally used in AR-15s. Its proprietary magazines are also polymer. The handguards are also polymer, and feature quadruple Picatinny rails.
The M&P15-22 can be used as a less expensive alternative for training with an AR-15 style rifle, as the rifle itself is much less expensive than most AR-15s, and the ammunition is often much less expensive than the .223 Remington/5.56×45mm NATO. The rifle features a safety and bolt lock that operate just like an AR-15's. The M&P15-22 can also be an alternative in jurisdictions that restrict magazine capacity for centerfire cartridges.
The M&P15-22 is also offered in a MOE (Magpul Original Equipment) version complete with an MOE pistol grip, MOE stock, MBUS sights, and a threaded barrel. This is available in Magpul FDE (Field Dark Earth), and standard black. The M&P15-22's lower recoil may also be used as a way to ease new shooters into the sport, allowing them to familiarize themselves with AR-15 controls without the fear of excessive recoil or noise. The 15-22 disassembly process is very similar to the AR-15 and S&W M&P 15. The lower receiver detaches from the upper with two captured pins. The lower receiver contains a standard M&P15 trigger assembly that is compatible with most AR-15 trigger groups. The upper receiver contains the bolt, barrel, and charging handle.
In 2016, Project Appleseed temporarily banned use of S&W MP15-22 rifles at their shooting clinics following a series of out-of-battery discharges, pending a full investigation and correction from Smith & Wesson. This was based on several incidents that occurred in multiple states, including one that injured a shooter on the line and another where multiple cartridges fired with but one trigger pull.

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