Mossberg 590A1

Tough enough for cops and soldiers
; .

Denny’s Mossberg 590A1 as described in the article. The Blue Force Gear sling
and SureFire light have been removed for clarity.

It’s been said if you give a soldier or cop an anvil for Christmas, he’ll break it by Valentine’s Day. Their equipment necessarily has to be reliable and capable of withstanding the rigors of hard use, day-in and day-out.

My shotgun of choice for the last several years meets the above criteria. It is a Mossberg 590A1. I’m not alone as it is the duty shotgun of choice for military and law enforcement agencies worldwide. It is the only pump action shotgun to pass MilSpec 3443E in the shotgun selection process.


The Magpul SGA comes with removable spacers to adjust the LOP (LEFT).
Sockets for stud-type sling attachments are on both sides of the stock.

Hard-Use Gun

Most readers are probably familiar with the Mossberg 500/590 series. They are almost as prevalent as Ruger 10/22 rifles. The difference in the 590A1 from their siblings is an upgrade with heavy walled barrels, metal trigger guard and safety. The trigger guard and safety on standard models are plastic and although the plastic parts will serve well in most roles, I have seen both parts break. The metal will hold up better with hard use.

All 590A1s have a nine-shot capability — eight in the magazine and one in the chamber — and 20″ cylinder-bore barrels with 3″ chambers. A bayonet lug is affixed to the magazine and with a bayonet attached, might be enough to cause a social justice warrior during a “peaceful protest” to move along.

Various models feature tactical tri-rail forends, six-position adjustable stocks, Picatinny rails on top of the receiver, specialty sight packages and either Parkerized or Marinecote finishes. Weight as it ships from the factory is 7.25 lbs.

My personal 590A1 (Mossberg model #51663) has a Parkerized finish with and adjustable rear ghost ring sight. The front sight is a blade on a serrated ramp with a red insert.

I think one of the best features of all 500 series Mossberg shotguns is the placement of the safety and action release. Located on top of the receiver, the safety can be manipulated easily by both right- and wrong-handed persons without changing the firing grip. The action release, located behind the trigger guard is equally ambidextrous.


A Magpul MOE forend and forward sling mount were selected for the 590A1 and
Denny’s personal 590. The bayonet lug will accept the M7 (M16) bayonet.

Lop It Off

The 590A1 has a 14.25" length-of-pull (LOP). Truthfully, it’s at the outer edge of comfort and good technique for me in shirt sleeves. Add a heavy coat, armor or load-bearing gear and the LOP becomes too long for almost everyone. It’s possible to shoot very well with a short stock (the Russian/Chinese SKS is an excellent example), but it’s hard to maintain good technique with a too-long stock. With a shotgun, a stock causing the shooter to reach farther to the trigger also increases perceived recoil.

To solve this, I added a Magpul SGA stock and MOE M-LOK forend. With two removable spacers the LOP can be changed from 12.3" to 14.3". I removed both of the spacers from my shotgun. The SGA stock has sockets for stud-type sling attachments on both sides and I used a Magpul forward sling attachment for the muzzle end.

The MOE M-LOK forend allows for the placement of a white light — a necessity on a fighting shotgun. I use a SureFire 500 lumen Mini Scout Light Pro. I also added a six-round TacStar SideSaddle to have extra shells immediately available. A Blue Force Gear Vickers tactical sling completed the package.


Load Out

I carry shells in the SideSaddle with the brass heads of buckshot facing down and the heads of slugs facing up. The person who taught me this technique explained in the dark, the shells can be told apart tactilely. This is logical and a good practice.

Along the same lines, feel the brass head of the shell as it is pushed into the magazine. Inadvertently placing it in backwards will result in a true jam, versus a malfunction that an immediate action drill can reduce. The open lifter on the 590A1 makes clearing the jam easier, but it is an involved process and takes time. In a critical situation it’s wiser to transition to a sidearm.

A common malfunction with the shotgun is short-stroking the action. The cure is to work the action like a rented mule; don’t worry, you won’t damage the gun, it was designed to be worked this way.

One downside of the shotgun is the amount of ammo on tap and it is wise to keep it topped off: shoot one, load one; shoot two, load two. In other words, load when you can, not when you have to.


Controlled Flight

There was a time when I suggested buying several brands of shotgun shells and pattern them in your shotgun to see which load performed best.

As they say, “that was then and this is now” and you can save yourself considerable time and money by going straight to the Federal Law Enforcement Tactical round with the FliteControl wad.

Federal offers this in both eight- and nine-pellet loading. I prefer the eight-pellet load because, although rare with the FliteControl wad, there is always a chance of a flyer and you are morally and legally responsible for each and every projectile launched.

Because of the way the FliteControl wad is constructed, there is virtually no spread at 10 yards. At 25 yards the pattern rarely opens up more than 8". A side benefit is the Tactical load has less recoil.

Although it’s still not a rifle, with the adjustable ghost ring sights hits out to 50–75 yards are possible using quality slugs.

The Hornady American Gunner 1-oz. slug is designed to hit point of aim at 50 yards with no hold over/under while still traveling at 1,038 feet-per-second with 1,046 foot-pounds of energy.


Heavy Duty

The only drawback I have found with the 590A1 is during a shotgun course, with a full payload and the 20″ heavy-walled barrel and magazine tube, it becomes heavy during repetitious range drills.

I also have a Model 500 with 18.5″ barrel and five-shot magazine to which I have added ghost ring sights and Magpul furniture. It duplicates the action and feel of its larger brother without the fatiguing weight after a long day on the range.

If you’re in the market for a shotgun tougher than an overcooked steak, the Mossberg 590A1 won’t fail you. The suggested retail price is $759.

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