Mossberg 590 vs 590A1: Is the Mil-Spec Upgrade Worth It at Home?

Two guns, one family

The Mossberg 590 and 590A1 look nearly identical across a gun counter. Both are pump-action 12 gauges built on the same family as the Mossberg 500. Both use Mossberg's top-mounted ambidextrous safety, dual extractors, twin action bars and an anti-jam elevator. Both have a magazine tube that opens at the muzzle end so you can remove the spring and follower for cleaning.

The differences are about materials and the barrel. According to Wikipedia's Mossberg 500 entry, the Model 500 and Model 590 have polymer trigger guards and safeties and standard barrels, while the 590A1 has an aluminum trigger guard and safety and a heavier barrel. Mossberg's own 590A1 pages list "MIL-SPEC construction," a "heavy-walled barrel" and a "metal trigger guard and safety."

So the question isn't whether the A1 is a better-made shotgun on paper. It is. The question is whether those upgrades solve a problem you actually have at home.

This comparison is an editorial reference built from Mossberg's specifications, retailer listings and published history. It is not a hands-on test.

Where the 590A1 came from

Mossberg designed the 590 in 1987 for military use, according to Wikipedia's history of the 500 family. The earlier 500 had struggled with the military's MIL-SPEC 3443 test protocol, which involved firing 3,000 shells with no more than two malfunctions.

Two details explain the A1's features:

• The heavy barrel was added at the U.S. Navy's request to stop barrels deforming when a shotgun was caught in heavy steel ship doors.
• The metal trigger guard answered the materials requirements of the 3443G revision of the specification.

The resulting M590A1 became the standard shotgun in the U.S. military. Mossberg's current 590A1 page describes it as "the most durable of our pump action shotguns," meeting MIL-SPEC 3443G, and offers it in Parkerized or Marinecote finishes.

Notice what those problems were: steel doors on ships, years of hard service in many hands, rough handling in vehicles. Those are real reasons. They just aren't the reasons most people buy a home-defense shotgun.

590 vs 590A1 side by side

Specifications vary by model number and change over time. Confirm the exact SKU on Mossberg's site before buying, especially sights, stock and length of pull.

The heavy barrel: what it does and what it costs

A thicker barrel wall resists denting and bending. That was the Navy's concern, and it is a real benefit if the gun will be dropped, banged against door frames or carried in vehicles for years.

The cost is weight, and it sits out at the front of the gun. Mossberg lists the 18.5-inch 590 7-Shot at 6.3 pounds; Ammunition Depot lists a 20-inch 590A1 Tactical at 7.25 pounds. Those aren't identical configurations, so don't read the gap as a precise barrel-only number, but the direction is clear: the A1 is the heavier gun.

Weight cuts both ways. A heavier shotgun soaks up a little more recoil, which some shooters appreciate. A heavier, more muzzle-heavy shotgun is also harder to hold on target while you clear a doorway, harder for smaller adults to handle, and more tiring to hold at the ready while you wait for police. If a smaller-framed person in your house may use the gun, the lighter 590 often makes more sense.

Metal trigger guard and safety: who benefits?

The polymer trigger guard and safety on the standard 590 are not fragile parts in normal use. They're the same style used across a huge number of Mossberg pumps in homes, patrol cars and duck blinds.

Metal parts make sense if you expect impacts, extreme cold or heavy use over many years. For a shotgun that comes out of a safe for range trips and spends the rest of its life locked away, it is a small durability gain. Some owners simply prefer the feel of a metal safety button under the thumb; that's a legitimate preference, but it's a preference.

Both guns share the same thing that matters most at home: a tang safety on top of the receiver that a right- or left-handed shooter can see and reach without changing grip.

Shared strengths you get either way

• Clean-out magazine tube. Both have the capnut design that lets you pull the spring and follower for cleaning and inspection, as Mossberg's product pages describe.
• Drilled and tapped receiver for an optic mount, on the models listed by Mossberg.
• A huge accessory market. Forend lights, side saddles, stocks and slings for the 590 family are everywhere, and most fit both versions. Check fit for heavy-barrel-specific parts like barrel clamps.
• The same manual of arms. Anyone who learns one can run the other.

Our 590 Tactical 6-shot vs 9-shot comparison covers the capacity and barrel-length decision, which matters at least as much as the A1 question.

Telling them apart on a used rack

Used 590s and 590A1s turn up often, and labels on a price tag aren't always right. A few quick checks, done with the action open and the gun verified empty, will tell you which you're holding:

• Look at the trigger guard. On an A1 it's metal; on a standard 590 it's polymer. Tap it with a fingernail if the finish makes it hard to tell.
• Look at the safety button on top of the receiver. Metal on the A1, polymer on the 590.
• Look at the barrel's muzzle. The A1's heavy-walled barrel is visibly thicker at the muzzle than a standard 590 barrel.
• Check the markings and model number, then look the number up on Mossberg's site to confirm barrel length, capacity and sights.

While you're at it, check the bore for pitting, cycle the action slowly to feel for grit, and inspect the magazine spring and follower through the clean-out cap. A rough used A1 is not a better buy than a clean, well-kept 590.

Setting up either one for the house

1. Light first. A forend light or a rail-mounted light is not optional on a home-defense shotgun. Our shotgun lights guide covers the options; Ammunition Depot's weapon light category has the common rail lights.
2. Fit the stock. A 13.87-inch length of pull is shorter than many shotguns, but still long for some adults. If anyone in the house struggles, look at adjustable stocks; Mossberg's 590A1 #50769 has a six-position stock listed at 10.5 to 14.25 inches.
3. Choose and function-test a defensive load. A common choice is a tight-patterning 00 buckshot load such as Federal Tactical FLITECONTROL 00 buck, which Ammunition Depot lists as nine copper-plated pellets at 1,325 fps with a rear-braking wad. Pattern it at indoor distances before you trust it. Browse more options in the 12-gauge ammo section.
4. Add a sling so the gun can hang while you use your hands for a phone, a door or a child.
5. Plan the storage. A long gun needs a safe, a locking rack or a quick-access long-gun safe. Our safe storage guide walks through the choices.

The verdict

The 590A1 is the toughest version of a famously tough pump, and the heavy barrel and metal fittings exist for good reasons. Those reasons came from ships, vehicles and military service, not bedrooms.

If you want the best-built version and don't mind the weight, buy the A1 and enjoy it. If you want the most useful home-defense setup for the money, the standard 590 plus a quality light, a sling, a safe and a few classes is the stronger package.

Editorial note: This is an independent editorial overview built from manufacturer specifications, retailer listings and published sources. We have not performed hands-on testing of the products discussed, and nothing here is a performance guarantee. Verify specifications, compatibility and the law where you live.

Affiliate disclosure: Some links on this page are affiliate links to Ammunition Depot. We may earn a commission if you buy through them, at no extra cost to you. Our editorial choices are not influenced by commissions. Check current price, stock and specifications directly with the retailer.