This is a factory Mossberg magazine for the 590M, holding 15 rounds of 12 gauge in a double-stack polymer body. The 590M is unusual and genuinely useful: a pump shotgun that feeds from a detachable box magazine rather than a tube, which means reloading is a matter of swapping a magazine instead of thumbing shells one at a time. That capability is only as good as the magazines you have for it, so spares are essential rather than optional. The stack geometry is engineered specifically for shotshell rims, which is the hard engineering problem this design solves.

In stock and ready to ship straight to your door from Dawson Defense, an Arizona-owned licensed dealer.