Military Weapons From The Past: Smith and Wesson Model 39 Suppressed “Guard Dog Gun”

Smith & Wesson developed its Model 39 handgun in the early 1950s in response to requests from the U.S. Army for a new, lighter service pistol chambered in nine-by-19 millimeter. When the initial interest from the Army evaporated, Smith & Wesson was left with a modern semi-automatic handgun — the company’s first modern automatic pistol since the 1924-vintage Model 32.

Developed by Smith & Wesson engineer Joseph Norman, the Model 39 was the first American-designed, double-action semi-automatic pistol on the U.S. market when Smith & Wesson introduced it in 1955. The Model 39 has an aluminum alloy frame with a carbon-steel slide and weighs just 11 ounces. It features a relatively short, four-inch barrel, fed from an eight-round single stack magazine. The Model 39 boasts a slide-mounted safety that decocks the weapon.

The Illinois state police acquired the weapon in 1967 and it eventually scored a military customer, too — when the U.S. Navy bought a special, suppressed version for special operators in Vietnam.

In 1966, the Naval Ordnance Laboratory developed a specially-modified version of the Model 39 at the request of deployed SEAL teams. The SEALs wanted weapons for silencing enemy guard dogs and sentries. The result — a range of suppressed pistols the special operators called “hush puppies.”

The Navy extended the Model 39’s barrel by an inch and threaded the muzzle to accept a suppressor. Engineers added a simple slide lock to allow the pistol to be fired in a single-shot mode, in order to minimize action noise. The magazine and magazine housing were adapted to accept a 13-round, double-stack magazine.

The large diameter of the suppressor housing required the Navy to raise the Model 39’s sights. The sailing branch also dovetailed the pistol’s backstrap to make it compatible with a wire stock for greater accuracy. The Navy designated the modified weapon the “Pistol Mark 22 Mod 0.”

The pistol came paired with the Mark 3 suppressor, which was five inches long and weighed eight ounces. The Mark 3 included a suppressor insert held in place by a spring retainer.

The insert was made of an aluminum capsule filled with four quarter-inch plastic disks or wipes. The disks were whole until the first round passed through them, making a channel for subsequent rounds. The capsule could be easily replaced. It had an expected life span of 24 rounds.

The Navy developed special ammunition, too. The Mark 144 round had a heavy, 158-grain, fully-jacketed projectile with a muzzle velocity of 950 feet per second. With the suppressor and Mark 144 ammunition, the pistol’s report was a mere 129 decibels.

Smith & Wesson produced between 110 and 120 pistols for the SEALs. Each SEAL platoon got a minimum of one Mark 22 Hush Puppy starting in 1967. The Mark 22 Mod 0 remained in service with the SEALs into the 1990s, when H&K’s Mark 23 Mod 0 finally replaced it.

This story originally appeared at Historical Firearms.

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