How many times can the 100+ year old pump action shotgun design be refined to keep shooters interested? Who knows, but it is pretty clear that we have yet to see any signs of hitting a wall. On its surface, the Mossberg 590M simply looks like a modified tube fed shotgun that accepts magazines, much like other scattergun platforms have done for decades.

However, the real innovation is in the magazines themselves. The perfection of the double stack shotgun shell mags is a development that has previously stumped designers – reliable stacking rimmed cases/shells is a challenge. Packing up to 20 rounds, the wide form magazines are obviously bulkier than their single stack kin, but the length savings is obviously noticeable.

The magazines are well built and rock in from front to back much like an AK magazine. A tongue and groove style system locks the magazine into the well securely with little play. Dropping a mag is a simple push button release and a slight push forward movement with a smooth, non-binding function. With the center of mass shifted back towards the shooter, shouldering a shotgun and 20 rounds of 12 gauge ammunition is surprisingly comfortable.

The 590M is impressive. It’s obvious that this wasn’t a last minute addition to Mossberg’s new product lineup.

Mossberg 590M Mag Fed 10-Round (50205)

This base model includes all of the field-proven features of Mossberg’s pump-action platform with an 18.5-inch, heavy-walled cylinder bore barrel; bead sight; black synthetic stock and forend; matte blue metal finishes; and 10-round, double-stack magazine. MSRP: $721

Mossberg 590M Mag Fed Tri-Rail 10-Round (50206)

For greater versatility, this version features a Tactical Tri-Rail forend with full-length bottom rail and dual side rails for easy attachment of lights and accessories; 18.5-inch heavy-walled barrel with interchangeable ACCU-CHOKE™ choke tube system (cylinder bore tube included); protective heat shield; Ghost-Ring sight; black synthetic stock and forend; matte blue metal finishes; and 10-round, double-stack magazine. MSRP: $801

Mossberg 590M

Based upon Mossberg’s proven pump-action platform, standard features of the 590M include non-binding twin action bars; positive steel-to-steel lock-up; anti-jam elevator; dual extractors; anodized aluminum receiver drilled and tapped for convenience of adding optics; heavy-walled barrel; convenient cleanout magazine tube; and universally-recognized, ambidextrous top-mounted safety. With the included 10-round magazine, these 12-gauge 2.75-inch pump-actions have a total round capacity of 10+1.

Innovation is at the core of the 590M with the detachable magazine’s uniquely-designed, integral stabilizing ribs which engage the magazine directly to notches engineered into the receiver, ensuring a positive lock-up. The all-steel, heated-treated magazine release button and housing are optimally-positioned in front of the trigger guard for quick, ambidextrous access for unloading and reloading the 590M. The location of the mag release does not interfere with cycling of the action. The well-executed design allows for proper balance, better swing and controlled-manipulation with a full-magazine located at the center of gravity point.

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 proprietary double-stack magazine provides greater capacity in less magazine length versus competitor’s single stack magazine. For greater shooting flexibility, 590M magazines are available in 5, 10, 15 and 20-round capacities and are designed for use with 2.75-inch shells only. Transition quickly from a target load, to buckshot, to slugs, to less lethal with the convenience of designated magazines.