OK not truly a black rifle topic I know, but thought the best place to ask. I picked up a S&W M&P 15-22 for cheap plinking practice and to give my sons something to learn on. Does anyone know of a mag coupler that will work with the S&W M&P 22LR mags? My 14 year old is gonna try out TAC Rifle this summer using this one and instead of finding a belt mounted carry system for a single spare mag (Courses of fire are typically 35-40 rounds). I thought coupling 2 on the gun itself would be a better way to go. I would actually like to get one that could handle Pmags too. Appreciate the advice.