Mossberg’s 590M Mag-Fed

Time To Get Pumped On Double-Stack 12-Gauge Firepower!

Holt’s test gun functioned perfectly, but he couldn’t get a skylined empty photo!
The gun shucks shells straight down.

With a capacity of 5, 10, 15, or 20 rounds, Mossberg’s new 12-gauge 590M Mag-Fed is yet another intriguing addition to their stable. Based on the only 12-gauge pump shotgun to ace the U.S. Military’s brutal Mil-Spec 3443 testing standard, the high-capacity 590M Mag-Fed feeds from a family of double-stack, detachable magazines offering up enough downrange firepower to suppress even the Inevitable Zombie Apocalypse.

A trend that has been building in the world of pump guns is for greater shell capacity and reloading speed. Three-Gun competitions and home-security concerns have certainly accelerated the trend.

Tubular magazine extensions are a tried-and-true method of adding additional shells to your cornshucker. Then there are the more exotic pump-action designs like the Kel-Tec KSG and ATS-15 bullpups feeding from dual magazine tubes and offering 12 and 15 rounds respectively. And don’t forget the AK-modeled Saiga with its 20-round drum.

Mossberg and Remington, on the other hand, have decided to modify their basic 590 and 870 platforms and go the detachable magazine route. But there is a significant difference. Remington chose a single-stack configuration holding either 3 or 6 rounds, while Mossberg added a clever twist by designing a series of compact double-stacks with capacities ranging from 5 to 20 rounds.

With a fully loaded 20-round magazine, the 590M tips the scale at about 10-3/4 lbs.

Mil-Spec Workhorse

Selecting their Model 590 as the basis for the detachable magazine version speaks volumes about the rugged capability of the 590M Mag-Fed variant. The government’s “Mil-Spec 3443” requirements for a replacement combat shotgun after the wear-and-tear of Vietnam are interesting. To meet the stringent specifications, the gun had to fire 3,000 consecutive rounds with no more than two malfunctions and with the development of no unserviceable parts. Plus, it had to continue to function under the most extreme environmental conditions. The Mossberg Models 500 and 590 were the only shotguns at the time to meet or exceed those standards, and Mossberg has been walking away with military contracts from around the world ever since.

The 590M Mag-Fed Heat Shield model shown here meets those standards with a heavy-walled 18.5″ barrel fitted with Mossberg’s Accu-Choke tube system (Cylinder Bore included) and carrying adjustable ghost-ring sights. It features non-binding twin action bars, a bolt with dual extractors that locks into the barrel extension and ambidextrous magazine releases and a tang safety. The MSRP for this model (with a 10-round magazine) is $810. A more basic model without the adjustable sights, heat shield and Accu-Choke system carries a price tag of $721.

Holt stopped this zombie officer with one round of No. 4 buck at 25 yards.

Each gun comes with a 10-round magazine that locks in like a bank vault with projecting
lugs engaging the frame. The button-headed mag release is ambidextrous and the Heat Shield
variant Holt used sports a set of adjustable ghost-ring sights.

Totally Non-Tubular

The new double-stack magazines for 2-3/4″ shells are built like a Mack truck from a self-lubricating polymer. You rotate them into the magazine well and they lock up like a bank vault. The secret is six stout lugs (or fingers) to engage matching locking recesses milled into bottom edges of the mag well.

The magazine feed lips are hardened steel and are fed from overmolded steel shell ramps. The follower features an anti-cant design to ensure flawless feeding and flawless it was during my testing. Maybe the most important internal element in the magazine is its heavy-duty music-wire spring designed to maximize service life, which is particularly important when storing loaded high-capacity magazines for extended periods of time. They’re not cheap. The 5-shot model sells for $101 — the 20-shot for $140.

Selecting a detachable magazine feed system makes a lot of sense. Reloads are instantaneous. It’s flexible, permitting you to transition from target loads, to buckshot, to slugs, to less lethal ammunition with a simple magazine change. A slightly more subtle advantage is the design places the weight of the rounds at the center of the gun adding stability while firing as opposed to extended tubular magazine designs in which the balance point continually shifts rearward as you fire. With the 15- or 20-round magazines in place, the 590M Mag-Fed may look odd and awkward, but with the weight of those rounds centered between your hands, it actually handles pretty well.

I was curious about the weight factor. On my Sunbeam scale, the 590M without a magazine weighed in at 7 lbs. With fully loaded magazines, the weight of the gun ran as follows: 5-round (8.5 lbs), 10-round (9 lbs. 6 oz.), 15-round (10 lbs. 3 oz.) and 20-round (10 lbs. 14 oz.).

In the civilian world I see two primary customers for Mossberg’s 590M Mag-Fed — tactical competitors and security conscious homeowners who would appreciate a magazine-fed shotgun capable of being loaded — or unloaded — in seconds.

It was fun to work with and the new magazine system proved utterly reliable.

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