No, I didn't mistake anything. The S&W M&P 15-22 is a purpose built AR15 style 22 Caliber rimfire rifle. I provided the link since you don't seem to be familiar with it. It's a hoot to shoot too...In my M15, I shoot 158 grain RNL for plinking and target shooting. Minimal leading, great accuracy, reasonable price.
AA (above poster) has mistaken the M15 -38 Spl. for a M18 22LR revolver I believe.
Chief38