Mossberg 590M Mag-Fed Shotgun: SHOT Show Quick Look

This brand new version of the venerable 590 feeds 12-gauge shells from detachable box magazines in 5-, 10-, 15- and 20-round capacities.

Hot on the heels of Remington’s detachable magazine pump shotgun, the 870DM, Mossberg had it’s hot new mag-fed beast on the firing line with some serious capacity on display.

The 590M is a 12-gauge pump-action shotgun with a 2.75″ chamber built on the company’s ultra-reliable 590 platform that uses double-stack detachable box magazines, which are available in 5, 10, 15, and 20-round capacities.

Initially, the 590M will be available in two configurations, a plain 590 version and a tactical version with a heat shield and rail sections for accessories.

The Mossberg 590M with its various magazines.
The Mossberg 590M with its various magazines. photo by Dave Maccar

Feeding shotshells reliably from a box magazine has long been the goal of gunmakers. Find out why it has been such a difficult engineering hurdle.

The Miracle of Detachable Box Magazine Shotguns

The 590M include non-binding twin action bars and the top part of the magazine is steel, so you don’t have a polymer mag trying to lock into a steel magwell. In fact, the extremely solid lock-up of the magazine is the most impressive part of this shotgun, along with the fact that the mags easily rock into place and are just as easily removed with an ambidextrous release button located just in front of the trigger guard that can be activated with the shooter’s index finger.

While the 590 has been around for quite some time, the new magazines are the real engineering achievement. I intentionally short-stroked the shotgun on the range, trying to get it to jam up, and just couldn’t do it.

Another shot of the 590M laid out with its various magazines.
Another shot of the 590M laid out with its various magazines. photo by Dave Maccar

According to Mossberg, the mags have uniquely-designed, integral stabilizing ribs which engage the magazine directly to notches engineered into the receiver, ensuring a positive lock-up. The location of the mag release does not interfere with cycling of the action. And the fact that the ammo is housed at the gun’s center of gravity, making for an extremely balanced shotgun.

The patented double-stack magazine is constructed with hardened-steel feed lips, over-molded steel shell ramps and an anti-cant, rounded follower to ensure reliable feeding. Other design features include an easy-grip, molded external shell; proprietary self-lubricating polymer magazine body; heavy-duty ASTM-A-228 music-wire magazine spring for prolonged service life; removable floor plate for ease of cleaning; and durable black oxide finish on the steel components.

The mag’s double-stack design also provides a greater capacity for less magazine length compared to the 870DM’s single-stack magazines.

A close look at the Mossberg 590M's magwell.
A close look at the Mossberg 590M’s magwell. photo by Dave Maccar