Smith & Wesson announced a new AR-style pistol chambered in .22 LR: the M&P15-22P. The M&P 15-22P is a polymer framed semi-auto pistol based on the S&W M&P 15-22 rifles.
The new S&W handgun has a 6″ carbon steel barrel with a 1:15 twist, and weighs 51 ounces (unloaded). The detachable magazine holds 25 rounds of .22LR ammunition. This is the same standard capacity magazine that is used in the M&P15-22 rifle. So, if you have one of those, you can swap mags between the two guns.
The M&P 15-22P features a full-length optics rail along the top of the gun, and a mini-quad rail for lasers, lights, can openers and Romulan cloaking devices. A swivel point attachment is also included for attaching a single point sling.