Ithaca M37 Trench Gun

The Army’s best combat pump shotgun is back: Inland’s reissue of Ithaca’s M37 Trench Gun.

Two top-shelf Ohio-based firearms manufacturers have partnered to bring collectors and shooters a fine reissue – I hesitate to call it a replica – of the vintage U.S. Army Ithaca M37 Trench Gun.

This retro military model is made by the Upper Sandusky-based Ithaca Gun Company for their Dayton neighbor, Inland Manufacturing. The latter is best known for their excellent reproductions of World War II M1 carbines.

The American martial tradition is no stranger to shotguns. Militiamen employed fowling pieces in battle during the Revolutionary War, and the Confederate Cavalry wielded sawed-off shotguns in the Civil War.

It was during World War I that you might say the Army got serious about shotguns. It was, after all, the biggest war they had fought to date. Close combat in the trenches, and especially night fighting, favored the massive firepower of fast-shooting pump shotguns.

Each 00 buckshot round blasted out nine .33 caliber pellets, increasing the chances of a lethal hit on the enemy. WWI trench guns could shoot exceptionally fast because they lacked a trigger dis-connector.

This allowed them to fire with every pump of the action as long as the trigger was held back continuously. Today we would regard this as a safety flaw, but to the doughboy standing in an enemy trench in 1918, that extra bit of speed was regarded as an edge.

The Germans hated facing shotguns, and even filed a formal complaint that using shotguns was a violation of the rules of civilized warfare – to no avail. The trench gun was born. While it distinguished itself in battle, the trench gun was by no means a common frontline weapon. Records suggest that fewer than 40,000 were procured during the war, compared to more than 2,500,000 service rifles.

WHAT DISTINGUISHED THE military trench gun, with its 20-inch barrel and cylinder bore, from the era’s civilian riot gun (what we would today call a tactical shotgun) was the military’s addition of a barrel heat shield, bayonet lug and sling swivels.

The 16-inch M1917 Enfield bayonet could be fitted to the muzzle, and the heat shield on the barrel was added to allow the soldier to safely grip the hot barrel during bayonet fighting. The riot gun was made for civilian troubles and the trench gun for war.

In WWI, civilian riot versions of Winchester Models 1897 and 1912 and the Remington Model 10 were modified as trench guns. In WWII, shotguns from quite a few other manufacturers were procured to meet the pressing needs of a much bigger war.

The standard models were all pump action: the Winchester M12 and M31, Remington M31, Stevens M520, and rarest of all (with less than 1,500 produced), the Ithaca M37. Still, it wasn’t enough, and the venerable Winchester M97 joined other pump and even semiauto models from Stevens, Savage and Remington to arm American soldiers for rear-area guard duty and combat action on the front lines.

Since these weapons were obtained directly from civilian manufacturers, they were usually finished in the same blued steel as civilian models. Combat use of the shotgun in WWII was largely a Pacific Theater affair, where the dense jungles and close-range encounters favored its strengths. Both United States Marine Corps and Army infantry units equipped the point man of patrols with a trench gun, and Marine units institutional memory of the trench gun’s role in fighting the Japanese in the jungles in WWII was carried over into our next jungle war against the Communist forces in Vietnam 20 years later.

By the mid 1960s, military stocks of trench guns and their M1917 bayonets were running low and new contracts were let for both. The guns came from Stevens (M77E), Ithaca (M37) and Winchester (Models 1200 and 870). The majority of these new shotguns were in the riot configuration. Trench guns from the Vietnam era are quite rare.

Those Ithaca M37 trench guns that were delivered were virtually identical to the WWII model, differing in their markings and their parkerized finish. The Stevens M77E was the most commonly issued shotgun in the Vietnam era, followed by the Ithaca M37.

THE MODEL 37 WAS BASED on John Moses Browning’s improvements of an old Remington design when Ithaca introduced it in 1937. It was a fine sporting shotgun, and proved to be an excellent combat shotgun.

It was the lightest shotgun in the American arsenal, at least a pound less than its peers, with the exception of the graceful Winchester M12, which was still half a pound heavier. The M37 was a couple lighter than the old M97.

Despite being light, it was very strong and well suited to the battlefield. The top and sides of the Model 37 receiver have no openings, so the action is much easier to keep clean because nothing can fall into it from above. Because it loads and ejects from the bottom, it was essentially ambidextrous.

It was also exceptionally strong. The inverted “U” design of the receiver protected the shooter from injury in the event of a case rupture and the barrel attached to the milled steel receiver by means of an interrupted thread like a cannon breech.

They were built to last generations, and can take a beating better than any other pump shotgun. In fact, the huge Los Angeles and New York City Police Departments eventually adopted this model for use.

During the Vietnam War, the Ithaca M37’s performance and reliability earned it the reputation for being the best combat shotgun in the Army’s arsenal.

INLAND MANUFACTURING’S reissue of the M37 trench gun has all the quality and ambiance of an original gun without the multithousand dollar price tag. Since it is actually made by Ithaca, the quality of manufacture is superb. Collectors of martial shotguns should not sweat buckshot worrying that these trench guns will be passed off as originals.

Though they are marked “RLB” with an Ordnance Corps flaming bomb on
the left side of the receiver like WWII era trench guns, the marks are not stamped in the metal like the originals are. Furthermore, the guns are marked with Inland’s name on the receiver and other historically incongruous laser engravings on the barrel indicating manufacture in Lower Sandusky, Ohio. Other differences include a 3-inch chamber instead of 2¾-inch, and, perhaps the most obvious marking never encountered on a vintage gun – the admonition “READ OWNERS MANUAL.”

As if that isn’t enough, you should know by now that WWII-era trench guns were blued, not parkerized. I guess an unscrupulous seller might change the barrel and claim this was a WWII-era M37 refurbished for use in Vietnam, but they can’t get around those receiver markings without a lot of metal work.

The reissue’s stocks are natural oiled walnut like the original military guns. The heat shield, brass front sight bead and bayonet lug look great too. I tested an original M1917 bayonet and it was a perfect fit. The slide release is on the right front side of the trigger guard. Unlike a Remington 870 or Mossberg 500, it requires very little motion to actuate.

The safety is a sliding push button type at the rear of the trigger guard. The action is smooth and solid with no ricketiness in it. In fact, the whole gun feels immensely solid. It weighs only 6 pounds, 11 ounces, but it feels like you could butt stroke an enemy senseless with it. Unlike the original gun, it will not fire continuously if pumped while the trigger is held back. Surely you had to see that coming.

Shooting the M37, you do sense its light weight in the felt recoil. The butt plate is just thin hard rubber so your shoulder gets it all. The 2¾-inch Winchester Super X and Federal Premium 00 buckshot I tested recorded average velocities of 1,242 feet per second and 1,243 fps, respectively, out of the M37’s 20-inch barrel. (Both were advertised at 1,325 fps.) The Federal Premium was much more consistent in shot to shot velocity with a standard deviation of 17 to Winchester’s 89.

Velocity was recorded at 15 feet from the muzzle with an excellent and very reasonably priced Competition Electronics PRO CHRONO digital chronograph I got from Brownell’s to replace the one I foolishly loaned to a friend who, unbeknownst to me, turned out to be a cold-blooded killer of chronographs. This one I’m keeping close hold on.

I SHOT MY TEST PATTERNS standing, offhand, at 25 yards, a range I thought would reasonably simulate a jungle encounter based on my limited experience hiking Bataan Peninsula jungle trails in the Philippine Islands.

I shot five-round test strings. That is actually all the M37 can hold if you fill the magazine and put one in the chamber. The early 1940s was not the era of high-capacity shotgun magazines. When you consider that the military rifles used by most nations at that time typically held only five rounds, a five-shot trench gun doesn’t seem that bad.

I chose standard 2¾-inch, nine-pellet loads to simulate the old brass cased military M19 loads used before plastic shells became common in the 1960s. My target was 22 inches wide by 25 inches high with a 3-inch aiming point. The cylinder bore (no choke of any kind) threw lethal patterns every time, but rarely did all nine pellets hit the target every time.

The Winchester Super X put 34 out of 45 pellets (75 percent) on the target. The Federal Premium put 37 of 45 pellets (82 percent) on the target. Both loads shot about 9 inches above the point of aim. The Winchester load seemed to pattern a bit more random than the Federal Premium, but, aimed at the enemy’s belt buckle, both would deliver devastating multiple hits to the upper body. As for the pellets that didn’t hit my generously wide 22-inch sheet, they could easily have hit another enemy soldier.

Broad patterns can cause collateral damage in a civilian encounter, but in wartime the ability to hit multiple targets with a single round is a good thing. While I see Inland’s M37 Trench Gun as aimed for the collector and historic military reenactor market, you wouldn’t be underarmed using it for personal defense. If they could fight their way through a few major wars, they’ll undoubtedly do fine after the EMP apocalypse.

The M37 shoots well, is virtually foolproof, and that 3-inch chamber opens up a lot of modern lethal and nonlethal load options. If short 12-gauge rounds will feed reliably, that might be one way to increase the M37’s magazine capacity. I know these mini-shells are made by Aguila, Herter’s and Nobel Sport, but could not get any in time to test the gun for this article.

If the M37 has a flaw, it is that in its trench gun configuration, it can’t be taken down without a screwdriver. The heat shield needs to be removed before the barrel can be rotated the necessary ¼ turn to dismount. In addition, you can’t take apart the receiver of any M37 without a long straight screwdriver to remove the bolt that holds the butt stock on.

That bolt is inside the buttstock, accessible only after removing the buttplate. On the upside, you don’t really need to take it apart to clean it. The only dirt you’re likely to get in it is some carbon from your smoking shells as they are ejected.

By design, it is a clean action. The online advertised retail price
for this top quality reissue of the M37 Trench Gun is about $1,200. That might seem like a lot to some. It’s more than your typical used civilian Ithaca Model 37, but thousands less than any M37 Trench Gun. One thing is unmistakable when you handle and shoot it. It is made as well as any gun can be made, and your great grandchildren will still be shooting it. For more info, visit or call them at (877) 425-4867.

Story and photos by Frank Jardim