The Ithaca Model 37 Riot Shotgun: Historical Lookback

U.S. troops have used shotguns to a greater or lesser degree in all of this country’s wars. Vietnam was no exception, shotguns seeing action with point men on patrols or MPs guarding installations or prisoners, among others. World II trench guns, such as the Winchester Model 12, Stevens 520-30, Stevens 630, and even the venerable and iconic Winchester Model 97 Trench Gun saw action in Vietnam. In addition to those shotguns in arsenals at the beginning of the conflict, some new riot shotguns were acquired for Vietnam, the most numerous of which was the Stevens 77E, of which a little over 69,000 went into Army or Marine inventories. It should be noted, though, that anecdotally, the Marines much revered their Model 12 Trench Guns.

Ithaca had produced a limited number of riot and trench shotguns in World War II, but after the initial order had concentrated on producing 1911A1 pistols. To give an idea of the rarity of the WWII Ithaca riot guns, I paid $5,500 for mine in 2017. As US military shotguns continue to rise in price, today it would probably be worth $7,500. During the Vietnam era, a limited number of Ithaca Model 37 riot shotguns were also purchased by the US Navy and saw action with the UDT and SEALs.

It should also be noted that a number of Model 37 riot guns were acquired for use by the South Vietnamese; some of these may have seen use by US advisors. An extremely rare variant of the Model 37 is a Trench Gun with heat shield and bayonet lug, 206 of which were acquired by the USAF. Ithaca Model 37 riot guns were popular with the SEALs and UDTs for their handiness but also for their “slam fire” capability.

As with the Winchester Model 97 and Model 12 Trench and Riot Guns, the Ithaca Model 37 did not have a disconnect that required the trigger to be released to reset after a round had been fired. As a result, a point man encountering multiple enemy troops could just hold back the trigger and quickly work the pump action while moving the barrel to sweep VC or NVA with buckshot: this was “slam fire.” There are positive and negative aspects of the Model 37’s bottom ejection. For example, when shooting around cover, empty shells ejected to the right might bounce back on the shooter, while those ejected to the bottom would not. On the other hand, when shooting prone quickly if the shotgun is not held so that the ejection port is a few inches above the ground, empties could block the ejection port.

In James Watson’s Point Man, an excellent book about the SEALs in Vietnam and their weapons, there is no mention of ejection of spent shells as an issue with the Model 37. Watson does laud the simplicity of the Model 37 riot gun and the fact that it could be easily washed down in a stream. The SEALs did make one interesting alteration to some of their Model 37 riot guns. For their Ithaca Model 37s, the SEALs adopted a spreader choke (aka “Duck Bill”) to stretch the pattern horizontally. This device was intended to give a point man a better chance of disabling multiple enemies during a meeting encounter or to sweep a boat deck. Initially developed by the USAF for defending aircraft on SAC bases, the spreader choke was added to many SEAL Model 37s. As SEAL weapons often saw hard usage, it was found that the “Duck Bill” sometimes would fracture; hence, reinforcing rings were added to many of the chokes.

Combat shotgun ammunition for riot and trench guns in Vietnam had to remain reliable amidst the humid conditions in Vietnam. During World War II, such conditions in the Pacific had proven paper shotgun shells unreliable. Thus, the M19 all brass buckshot rounds had been developed late in World War II. During the early years of the Vietnam War, the M19 rounds remained in use; however, as the supply of M19 rounds became depleted, the XM162 00 buckshot load using plastic cases, which would not swell in humid conditions as paper shells had in WWI and WWII. Also developed was the XM257 #4 buckshot load. This load would have been of special interest to Navy Special Warfare personnel, as the duck bill chokes were more effective with the larger number of #4 buckshot in an SM257 shell.

Other specialized loads were developed for combat shotguns during the Vietnam War. “Whirlpool” 12-gauge shells loaded with flechettes were tested, which offered better range but less close-range stopping power. Since the SEALs/UDTs and others using combat shotguns normally chose them for close range lethality, the flechettes saw little combat usage. There were also experimental integrally suppressed shotgun shells for the SEALs. Most lethal work by the Ithaca Model 37 in Vietnam, though, was done with 00 or #4 Buckshot.

To carry shotgun shells in Vietnam, the updated version of the WWII M1938 12-round pouch was available. However, the SEALs/UDTs would have chosen something that held more rounds. Stoner 63 machinegun magazine pouches, WWI grenade pouches (many of which in new condition remained in military inventories or for sale in surplus stores), or whatever other bags or pouches were available.

The Ithaca 37 was produced from 1937 until today with over 2,000,000 having been produced. In addition to the US armed forces, it was the choice of the LAPD and NYPD for years. Fans of Adam-12 will remember seeing it on many episodes. However, Ithaca did away with the “slam fire” capability of the shotgun in 1975, thus making it less appealing as a combat shotgun. By then, the U.S. armed forces had begun using the Remington 870 and by 1979, the Mossberg 500 series of shotguns had been adopted for military use.

Shooting a Circa 1967 “Slam Fire” Ithaca 37 with a Duck Bill

I took my Ithaca 37 along with 2¾-inch 00 Buck Shot and #4 Buck Shot to see how the “Old Sailor” had held up. Mine was fitted, before I acquired, it with a Glow Worm front sight, which is easier to see than a standard bead and which I found allowed me to acquire targets faster. I set silhouettes up at varying distance and spaced apart to simulate “meeting engagements” for a point man. I engaged single targets out to 35 yards and multiple targets using the “slam fire” capability at 15 and 25 yards.

As I have found in the past, the Ithaca 37 riot gun is light and handy, allowing quick engagement. The ribbed forearm is compact but allows a good grip for fast operation. Its cross-bolt safety is easily thrust off with the trigger finger as it moves towards the trigger or pushed on with the thumb of the shooting hand. Reloads through the loading port, which is also the ejection port, are easy. The one negative on the controls was operation of the slide release, a thin serrated lever in front of the trigger guard on the right side of the shotgun. I found this release hard to operate with the trigger finger.

Because the Ithaca 37 riot gun is light, recoil is more noticeable than with heavier trench guns, for example. It isn’t unpleasant but it does slow repeat shots even with the slam fire capability. With my Winchester Models 97 or 12 Trench Guns, which are also capable of “slam fire,” their weight allows me to get onto the next target a little faster for repeat shots. At 25 yards and 35 yards, the Model 37 riot gun’s “Duck Bill” seemed to spread the pellets of #4 Buckshot horizontally. At 15 yards, the pattern remained almost circular. I did “slam fire” patterns at 15 yards and found that patterns remained mostly circular with a little spread horizontally. At closer ranges, the 00 Buckshot spread more horizontally than the #4 Buckshot. I probably overuse the word “iconic” for firearms I like, but the association of the Ithaca Model 37 Riot Gun with the UDTs (became SEALs in 1983) and the SEALs in the Mekong Delta during countless close quarters engagements I think cements the Ithaca 37 riot gun in U.S. special operations history. Just the words “Slam Fire” and “Duck Bill” do that! I’ll give James Watson the final word from his book Point Man: “Other weapons were in the gun shed; including the Remington 7188 full-auto shotgun.

When the weapon had first arrived, Bob had grabbed on to it as the best thing since sliced bread. Since the episode with the ants, I had started carrying a shotgun, a five-shot Ithaca Model 37. Bob tried to convince me that the Remington 7188 was the weapon for a point man to carry. But I considered it just too heavy. Besides, my pump-action repeater was much more reliable than that complicated full-auto weapon. My favorite shotgun ammunition was the XM-257 round with the hardened-lead #4 buckshot. The twenty-seven pellets in the shell would knock down any VC I aimed at, which was exactly what I wanted. The flechette shells that were sent to us later would certainly kill a man, at even longer ranges than the XM-257. But the sharp-pointed little flechettes—they looked like finishing nails with fins—wouldn’t stop a man as quickly as a load of #4 buckshot.”

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