Mossberg 12 Gauge Mil Spec Shotguns

Mossberg Mil Spec Shotgun

By Nick Jacobellis.

There are three war fighting and crime fighting shotguns that continue to serve in a front-line capacity. Even though more rifles and handguns are carried by armed professionals, shotguns also continue to serve in a front-line capacity and serve well. The use of shotguns in police work goes back to the days of the old west, when lawmen augmented their armament, by carrying a double barrel/side by side shotgun. Many of these shotguns had barrels that were cut back, or shortened in length, to make them easier to wield in close quarters.

During World War I, 12 gauge shotguns known as “trench guns” were carried and used by certain U.S. troops. The shotgun was such a feared weapon, that Germany formally protested the use of these firearms by American troops. Needless to say, the German complaint was ignored and the Americans continued to carry their issued shotguns, while fighting in the trenches.

In the period known as the Roaring Twenties, Prohibition and the Gangster Era, law enforcement officers in the U.S. also included shotguns in their armories for a reason. During World War II, the United States in particular, once again made 12 gauge shotguns available for use by their military personnel.

A very interesting true story about the use of shotguns during World War II, is documented in author and U.S.M.C. Lt. Colonel Kerry Lane’s book entitled, Guadalcanal Marine. In this book, Lt. Colonel Lane documents how he ended up electing to carry a pump action 12 gauge shotgun, when he was preparing for the invasion of Cape Glouster. According to Lt. Colonel Lane, Colonel Chesty Puller made it possible for him to do so, because Colonel Puller requested 10,000 rounds of 12 gauge buckshot ammunition, for use by the U.S. Marines, who were expected to take part in the up coming invasion of Cape Glouster. When a U.S. Army General from the Quartermaster Corps questioned the reason why Colonel Puller requested such a large number of shotgun shells, a Marine Lieutenant reportedly responded and said, “To Kill Japanese.” When the Army General informed this Marine Lieutenant, that it was a violation of the Geneva Convention, to use shotguns loaded with buckshot ammunition in combat, the Marine officer, who was acting under the instructions of Colonel Puller, informed the Army General, that “Colonel Puller didn’t give a damn about the Geneva Convention any more than the Japanese did when they bombed Pearl Harbor.”

After having served on Guadalcanal, Colonel Puller knew how intense fighting in the jungle could be. As a result, he obviously respected the fighting qualities of a pump action shotgun, as well as the stopping power of 00 Buckshot ammunition. It is important to note, that at that time, shotgun ammunition / “shells” that were manufactured for wartime use, were made of brass. This was done, because the alternative at the time, was to use a heavy paper/cardboard to construct the cases that contained the actual steel pellets. Even though this manufacturing process made wartime shotgun ammunition heavier to carry and more expensive to make, using brass cases made shotgun ammunition able to withstand exposure to harsh operating conditions.

In the post war years, British troops carried semi-automatic 12 gauge Browning Auto 5 shotguns during the Malayan Emergency. During the Vietnam War, various 12 gauge shotguns were once again pressed into service and were carried by certain front line U.S. troops, as well as by other personnel.

Shotguns known as “Riot Guns” were also widely used by U.S. law enforcement officers before the widespread adoption of the “patrol rifle.” During the Miami Vice Era of the Drug War, I carried two different government issued 12 gauge Parkerized Remington Model 870 pump action shotguns. One was a standard 870 with an 18-inch barrel and the other was an 870 with a cut down 14-inch barrel. Between these two variants I preferred the 870 with the shorter barrel, because this model was better suited for vessel boarding operations and clearing rooms. When I flew drug interdiction missions in U.S. Customs aircraft, including in a Black Hawk helicopter, I occasionally carried an issued Remington 870 with an 18-inch barrel, when I wasn’t carrying my government issued Colt CAR15. I also owned two Parkerized Ithaca Model 37 12 gauge pump action shotguns; one with wood “furniture” and one with a pistol grip.

Bear in mind, that back in the day, we used standard velocity 12 gauge 00 Buckshot, Number 4 Buckshot and Rifled Slugs. We did so, because Reduced Recoil shotgun ammunition was not available at that time. It was also in the last two decades of the 20th Century, that 12 gauge Mossberg pump action shotguns started to become increasingly more popular with legally armed citizens and law enforcement agencies/individual officers. This was especially the case, after Mossberg shotguns were adopted by the U.S. Armed Forces. In fact, Mossberg pump action shotguns were the only 12 gauge shotguns, that were able to meet the extremely demanding U.S. Armed Forces Military Specifications (Mil Spec) 3443 requirements. This was achieved, because all three Mossberg pump action models (the 500, 590, and the 590A1) have complete parts compatibility and were able to pass a grueling 3000 round 00 Buckshot endurance test. Mossberg Model 500, 590 and 590A1 pump action shotguns met these rather rigorous standards back in 1979.

From the Desert War in Iraq Through the Global War on Terrorism

Even though Mossberg shotguns were a proven design by the late 1980s, the reputation of the Mossberg Model 500, 590 and 590A1 skyrocketed to an all-time high, when these amazing pump action 12 gauge firearms were subjected to the rigors of desert warfare. It was during Operation Desert Storm in Iraq, that Mossberg Mil Spec shotguns passed one of the most grueling environmental tests imaginable. This occurred when numerous Model 500, 590 and 590A1s remained operational under some of the most adverse operating conditions imaginable. I am of course referring to Mossberg Mil Spec shotguns being used by U.S. military personnel in a very sandy environment.

The use of pump action Mossberg Mil Spec shotguns continued into the 21st Century, when the United States became involved in The Global War on Terrorism; a conflict that involved U.S. and Coalition/Allied Forces fighting once again in Iraq, as well as in Afghanistan. Just as in prior combat deployments, Mossberg shotguns were utilized by force protection personnel, for riot control, for personal protection and as a breaching device. This last application was essential for U.S. military personnel, while searching for high value targets and while conducting urban warfare, where it was essential to quickly gain access to locked buildings and rooms. A pump action Mossberg shotgun in the hands of military personnel were also ideally suited to be used in Close Quarters Battle situations. Mossberg Mil Spec shotguns also served at sea onboard U.S. Navy and Coast Guard vessels and have held up to another type of harsh operating conditions, involving the continuous exposure to salt air and water.

After the terrorist attacks on 9/11/01, tens of thousands of Mossberg M500, 590, and 590A1 12 gauge shotguns served with distinction during The Global War on Terrorism. Mossberg Mil Spec shotguns continue to serve in a front-line capacity in 2022, with a large number being provided to the Ukrainian Armed Forces.

To give you a better idea of the popularity of Mossberg Model 500, 590 and 590A1 Shotguns, the following is a rather impressive list of nations, that utilize these outstanding firearms, in various law enforcement and or military applications: The United States, Canada, Mexico, Colombia, Guatemala, Bermuda, Brazil, Bolivia, Chile, Argentina, Iceland, the United Kingdom, France, Italy, Germany, Austria, the Netherlands, Sweden, Poland, Lithuania, Croatia, Bulgaria, Hungary, Malta, Belarus, Serbia, Mongolia, Georgia, Lebanon, Jordan, Bahrain, Egypt, Iraq, Algeria, Chad, Sudan, Nigeria, Cameroon, Rwanda, Somalia, Kenya, South Africa, Mozambique, Madagascar, Lesotho, Pakistan, Afghanistan, Kazakhstan, India, Thailand, Vietnam, Cambodia, Bangladesh, Malaysia, Indonesia, Australia, Myanmar, Laos, South Korea, Japan, Philippines, Taiwan, Solomon Islands, Tuvalu, Fiji and New Zealand.

Field Testing Mossberg’s Top Go To War Shotgun

Because tens of thousands of Mossberg 12 gauge Mil Spec shotguns earned their stripes while being carried in two different desert wars, as well as in the harsh operating conditions of Afghanistan, I conducted my field test with a 590A1 SPX in high desert terrain. During this evaluation, standard velocity 00 Buckshot, Number 4 Buckshot, Rifled Slugs, Reduced Recoil 00 Buckshot and Reduced Recoil Rifled Slugs were fired through a Mossberg 590A1 SPX. I decided to feature a 590A1 SPX in this review, because this particular firearm is THE MOST well-equipped Mil Spec pump action shotgun on the market today.

Here’s why:

The Mossberg M590A1 SPX Model is equipped with an excellent set of Ghost Ring Sights, that includes a very easy to acquire front sight blade, that is fitted with an orange insert. While I have never had a problem using a front bead sight on pump action shotguns, the high viz Ghost Ring Sights on the 590A1 SPX make this shotgun more user friendly, especially when shooting Rifled Slugs. The rubber pad on the end of the polymer stock is also well designed and helps absorb the sharper recoil that’s produced by standard velocity shotgun ammunition. When using Reduced Recoil ammunition, the 590A1 SPX is even more comfortable to shoot.

The 590A1 SPX also has an 8 plus one round capacity and is very easy to keep loaded, if you have been properly trained to use a tube fed shotgun in a Close Quarters Battle Situation. In order to help the action operate smoothly, when you break in a new shotgun, I highly recommend that you apply some Ballistol, or some other lubricant on the rails.

The SPX is also fitted with a double walled 20-inch barrel, a Parkerized Finish and a bayonet lug. Even though the 590A1 SPX Model is fitted with a 20-inch doubled wall barrel, this model is very well balanced and weighs 7 pounds unloaded, which is lighter than other pump shotguns that have fewer features. This includes other pump action shotguns that have slightly shorter barrels. That’s impressive.

One of the reasons why I am a huge fan of the 590A1 SPX, is because this shotgun is manufactured with a factory applied Parkerized Finish. I developed a profound respect for a Parkerized Finish, after seeing how well numerous firearms with a Parkerized Finish were protected from corrosion, after years of service in harsh operating conditions.

Closing Remarks

The record speaks for itself. Mossberg Mil Spec pump action 12 gauge shotguns have reliably served with tremendous distinction, in some of the most demanding conditions imaginable for over 40 years. As a result of this outstanding track record, I decided to add a Mossberg 590A1 SPX model shotgun to my battery of personal defense weapons. If you are in the market for a 12 gauge pump action shotgun, it will definitely be worth your time, to examine the lineup of Mossberg Mil Spec shotguns.

Author: Nick Jacobellis is a Medically Retired U.S. Customs Agent and a former NY police officer who was physically disabled in the line of duty while working undercover as a federal agent. To date, the author has published 221 magazine articles and ten action-packed non-fiction, historical military fiction, and fiction police procedural books: Controlled Delivery Books One and Two, The Frontline Fugitives Books I, II, III, and IV, Buck Banderas U.S. Marshal Books One, Two and Three, A Special Kind of Hero and The K9 Academy-The Second Edition. These books have received 5 Star reviews and are available on (US) and (UK). The author was born and raised in Flatbush section of Brooklyn N.Y. and has an BS Degree in Police Science from John Jay College of Criminal Justice.

Photo: Photo of author testing a Mossberg 590-A1 12 Gauge Pump Action Mil Spec Shotgun. Photo by Rick Batory, 2022.

Article: This article was previously published by Republished with the permission of the author and