Aimpro/Mossberg Model 590A1 Predator 12 Gauge Shotgun

By Randy D. Smith

Randy with Aimpro/Mossberg Model 590A1 Predator 12 Gauge Shotgun.
Randy with Aimpro/Mossberg Model 590A1 Predator 12 Gauge Shotgun. Photo courtesy of Randy D. Smith.

I believe that a good shotgun is the most versatile hunting and home defense weapon on the civilian market. Nothing will back down a home intruder quicker than the sound of a shell being cycled through a pump action shotgun mechanism and the sight of a 12 bore cavity looming in his direction. If the threat doesn’t back off? A load of buckshot is devastating at short range without penetrating most walls still left standing behind the target. Shooting anything at close range with a load of buckshot is a grizzly thought, but when push comes to shove, a shotgun shoves very hard indeed.

A shotgun not only functions admirably in a wide variety of hunting situations, but also it is a fine choice as a survival tool. Shotguns can take small game without destroying the meat with light loads and heavier slug and buckshot loads can bring down most intimidating animals. The main drawbacks are the weight and bulk of shotgun ammunition. For extended periods of outdoor activity, a large supply of 12 gauge ammo can be unwieldy. A shotgun’s capabilities and limitations must be thoroughly understood for any self defense or hunting purpose. A shotgun is not some miracle machine and is only as good as the shooter’s training, accuracy and experience. Its presence alone will not insure anyone’s safety. A shotgun must be backed up with skill, courage, accurate shot placement and the determination not to be a victim, no matter what the cost.

As decades of hunting lie behind me (and I hope a few more in front), I have come to appreciate a good shotgun more than any other firearm. When the threat of a possible bear encounter arose on a recent Montana backcountry hunt, I loaded three rounds of 3” Magnum 00 Buckshot into my pump action shotgun and continued on down the trail with some confidence that I could, if I had no other choice, turn an aggressive brownie from an attack. A confrontation didn’t happen. I figured it probably wouldn’t. You never know for sure and that 12 gauge pump action shotgun gave me an extra margin of self-reliance and assurance.

The gun I carried that day was a custom Mossberg 590A1 Predator assembled and tuned by AimPro Tactical of Golden, Colorado ( AimPro works with police departments, security firms and private citizens to provide not only tactical weaponry, but also law enforcement and civilian firearms training. Aimpro will either build or convert any Mossberg Model 500 or 590 pump action, or Model 930 semi-auto to your specifications. The company will do action work, refinishing, barrel treating, Mag-Na-Porting, or install choke threads on Mossberg shotguns. Their custom shop offers a wide variety of finish and tactical options.

The Model 590A1 Predator test gun I carried is especially designed for predator hunting and came with a Pro-Factor PF1 modified choke (www. I requested the gun as part of a series of tests and experiments I wanted to conduct on predator calling shotguns and loads. I was attracted to the Aimpro Predator, because it is one of the few shotguns advertised as being designed exclusively for predator hunting and it is based on the familiar Mossberg pump action platform.

The Model 590 Mossberg is a tactical version of the original Model 500 pump action sporting shotgun, which was introduced in the 1960’s. The 590 was originally designed in the 1980’s as a heavier version of the Model 500 in order to meet military specifications. The 590A1 did so admirably, by passing the U.S. Military Mil-Spec 3443 standards. To my knowledge, it is the only pump action shotgun to do so.

A basic 590A1 comes with a 20” heavy profile barrel, six or eight shell capacity magazine tube, ghost ring rear sight with an orange blade, Parkerized finish and several synthetic stock options. The receiver is drilled and tapped for scope mounting with a Picatinny rail. Like all Mossberg shotgun bolts, it has two extractors to enhance shell removal. An accessory lug underneath the barrel’s mag tube support rings allows for a sling swivel crew or a bayonet lug.

The safety slider is located on the tang of the receiver. This feature allows for either right or left handed persons to operate the safety without losing contact with the trigger. The slide release is mounted behind the trigger guard. The 590A1 has a cylinder bore choke that patterns 00 Buckshot well and allows a switch to slug loads without a choke change. The chamber is three inches long, allowing the gun to chamber either 2-¾" or 3" shells. Interchangeable chokes are not an option.

The 590A1, at 7.5 pounds, is heavier than the standard Model 500. The added weight aids in recoil management and gives the shotgun a very solid feel. This shotgun will feed and extract shells with complete reliability.

The Aimpro Predator is an enhanced version of the 590A1. It has interchangeable chokes, Hogue synthetic forearm, buttstock with an enhanced recoil pad, sage colored matte finish, receiver mounted scope rail and sling swivel studs. Aimpro threads for the Mossberg Accu-choke are the same as the Win-choke and Browning Invector chokes.


  • Supplier: AIMPRO Tactical, 16015 W. 4th Avenue, Unit 4, Golden, CO.
  • Gauge: 12
  • Chamber Size: 3”
  • Capacity: 6
  • Barrel: 20” heavy-walled
  • Sights: Picatinny rail for scope mount
  • Safety: Tang mounted built to Mil-Spec demands
  • Choke: Interchangeable using standard 500 thread pattern
  • Length of Pull: 13-¾”
  • Finish: Parkerized in sage green
  • Stock and Forearm: Hogue Soft Touch with high performance Aimpro recoil pad.  Sling mount studs are present.
  • Weight: 7.5 lbs.

No greater choke constriction than modified should be used for 00 Buckshot or slug use. This particular shotgun patterns #4 and #1 buckshot loads through the Pro-Factor Modified choke very well. I have had the best 00 Buckshot patterns in several shotguns using improved cylinder or cylinder bore chokes. My best patterns with Hevi-shot T-shot, #1 Buckshot and #4 Buckshot have been with Full or specialized chokes, such as Carlson’s Dead Coyote choke for Hevi-shot Dead Coyote loads.

My best patterns for turkey hunting come from extra-full chokes using special turkey loads. I tested a Comp-N-Choke XX-full choke in this gun shooting 3” Winchester Supreme Extended Range Coyote loads. This load uses #B Bismuth shot. Patterns were surprisingly tight and solid at 50 yards. It rivaled the much more expensive 3-½” Hevi-shot T shot loads I use in my 835 Mossberg, with substantially less recoil. I have continued to call predators with this choke and load.

The trigger is not Mossberg’s LPA adjustable model, but it is smooth and crisp. I had no difficulty managing the gun’s recoil with a wide variety of moderate and heavy loads. The barrel is not ported. Many opt for this option.

I replaced the company supplied scope with my Bushnell Banner 1.5-4X circle reticle scope on tall rings. I prefer a circle reticle scope for hunting coyotes, as it speeds my target acquisition time. The original scope was mounted on low rings, which slowed my target acquisition. A red dot or reflex sight could be mounted, but I intended to also use the gun with slugs and I wanted a magnification option. In spite of the fact that modern electronic sights are very reliable, I also did not want to depend on batteries and have been very pleased with the Bushnell Banner on a variety of shotguns. For calling, I keep the scope on the 1.5 magnification setting. I also added an inexpensive cobra style sling for packing the gun into the backcountry.

I patterned a variety of predator rounds and settled on the Winchester Supreme Extended Range Coyote Load. I was also partial to Fiocchi 2 ¾” #4 Buckshot load with an IC choke. Recoil is a bit lighter with superior patterns out to 40 yards.

When I used this gun for calling wolves in Montana, I loaded 3” Winchester #1 Buckshot loads. I was unfamiliar with #1 Buckshot loads before these tests. Typically, there are 24 pellets in a #1 Buckshot load compared to 27 in a #4 Buckshot load. This load patterned very well through the modified choke and was a bit heavier for the larger sized wolf.

I used mouth calls in generally thick mountain pines, while my hunting partner carried a .270 Ruger bolt action rifle. Not knowing what to expect, I carried the shotgun for the majority of the hunt, in case wolves came in on the run or surprised us at close range. Unfortunately, I did not have the opportunity to use it on a wolf. We backpacked and trekked into some isolated locations in a variety of weather conditions ranging from hot and windy to snowy and still. The gun handled and carried very well throughout the hunt.

Coyotes are another story. This gun banged the heck out of several song dogs. On my second November outing with the Predator I scored a double. I called in two nice sized adult coyotes in a pasture heavily covered with three-foot tall sagebrush. They came in side by side, which is unusual, as one coyote often trails the other by a few yards. They held up at 30 yards, because of my movement to reposition for a better shot angle. I dropped the first one on the spot. The second dog turned and made a ten-yard retreat while I shucked and chambered shells. As he swung to the right I gave him a dose of Winchester Supreme Extended Range Coyote load. He rolled into the sage and did not recover.

I compared the Aimpro Predator to two other pump shotguns I have often used on predator hunts. The Predator is heavier and much more compact than my Mossberg 835 turkey gun. It is only slightly heavier and a bit more compact that my Ithaca Deerslayer. The Deeslayer is equipped with a 19” smooth bore slug barrel, 1.5-5x Konus scope and no choke constriction. I installed an IC Accu-choke in the Predator and compared 50 yard slug groups using Federal 2-¾” Tru-Ball Foster style rifled slugs. Both shotguns will cloverleaf this load on target from a bench rest. I took the Predator on a Kansas whitetail deer hunt, using it for still hunting thick stands of cedars, the same conditions for which I use the Deerslayer.

I like smooth bore pump shotguns for this style of deer hunting, even though there are no slug gun mandates in either Kansas or Oklahoma. Still hunting deer shots in heavy cedar woods are seldom longer than 70 yards. Deer are usually on the move. One ounce slugs are very lethal at close range and usually leave significant blood trails. Slug guns are also very quick on backup shots. I have used lever action 30-30’s, 308 Marlin and .45-70’s, as well as pump action and semi-auto Remington rifles in the same areas. All of them are effective. I have had my best luck with open sight 30-30’s and scope mounted, pump action 12 gauge slug guns. I don’t need the extra range of the other rifles. The 30-30’s and slug guns are quick on target. I have also tested rifled shotguns with sabot loads, but I don’t need the added range or expense of these rounds. I simply go to a rifle when the country opens up.

The advantages the Predator has over the Ithaca are the interchangeable system and 3” shell capability. The Predator will produce much tighter patterns at longer ranges. The Ithaca will produce decent patterns out to 40 yards using #4 buck loads, but patterns get awfully thin beyond that. The Predator is still effective at 50 or 55 yards.

My Mossberg 835 is an overbored 12 gauge capable of shooting 3.5” rounds. It is effective out to 60 yards using the Carlson’s Dead Coyote choke and Hevi-shot Dead Coyote rounds. I have taken standing coyotes at that range with this load and choke. Precise aim must be taken and recoil is significant. Dead Coyote loads are also expensive. I patterned 3” Dead Coyote T-Shot loads in the Predator using a Full Accu-choke. The pellet count advantage within an 8” circle of the 3.5” load was marginal at 50 yards. At 50 yards, I felt that I was just as well off using the XX full choke matched with the Winchester Supreme Extended Range Coyote in the Predator, as I was using the Dead Coyote loads in either gun or either choke. When predators are taken at that range with any shot load there can be a significant 10% pattern variance from one shot to the next. As long as I’m able to get 7 pellets inside an 8” circle, I’m probably going to take a coyote or bobcat down.

You have to ask yourself just what you want a shotgun to do. In most cases, I will switch to my rifle if the shot is 50 yards or longer. Shot loads group erratically beyond that range. The vast majority of shotgun kills I have when calling are from 30 to 45 yards. Any of these guns and loads of #1 buckshot, #4 buckshot or the specialized heavier than lead rounds will manage this.

Yes, I have seen and heard experiences of shotguns being used effectively out to 70 yards and I don’t doubt the possibility of such performance. However, when does luck enter into the equation? The goal, as I see it, should be consistent, humane kills with minimal wounding or crippling shots. For that reason, I draw the line at 50 yards with specialized shotguns and loads, 40 yards with most.

As I write this, I am going into the heart of winter coyote calling season. This Aimpro Predator has already seen a lot of hard use and the finish shows it in a couple of places. I’ve shot it enough with heavy loads that I’ve had to tighten and secure the rail screws with Lock Tite. I have not experienced a single missed feed, jam, or misfire with over a hundred heavy test and hunting rounds fired. This is a versatile and rugged shotgun that will perform with the best in the industry. It will be my first choice for the rest of the season. With a gun of this quality it could easily be a first choice for the rest of my life.

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Copyright 2012 by Randy D. Smith and/or All rights reserved.