Strange Guns: Gyrojet Pistol

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The Gyrojet pistol is a weapon developed in the 1960s by MB Associates founded by nuclear weapons researcher Bob Mainhardt and arms designer Art Biehl . Instead of firing bullets, it fires miniature rockets. Each containing their own rocket propellant.

The Gyrojet is a cartridge that looked like a .45 caliber pistol round. Ordinary bullets are propelled down the barrel of a gun by an explosion. Gyrojets are powered by onboard rocket fuel. This means the gun itself can be simple, as the barrel and chamber don’t have to contain an explosion. Gyrojets are stabilized by spinning: The angled rocket nozzles would spin the bullet up to rotational speeds higher than most rifle rounds. At maximum speed, a Gyrojet round had 2x the kinetic energy of a .45 caliber pistol round it resembled.

Type: Single action
Caliber: 13x50mm rocket
Weight unloaded: ~ 620 g
Length: About 300 mm
Barrel length: n/a
Magazine capacity: 6 rounds

-- modernfirearms.net

The Gyrojet pistol was sort of like a hand-held, multi-shot rocket launcher. It was advertised as silent and capable of firing under-water, but in real life it turned out to be very unreliable and inaccurate. Furthermore, these weapons were rather not effective at point-black distances, gaining its full power only at ranges of about 40 to 60 meters. Few of these Gyrojet pistols were used in the Vietnam War in the hands of U.S. military officers, who bought them with their own money, but no reports of successful use ever appeared, and by the late sixties the Gyrojet project was doomed to fail.

Maybe the only plus factor of this weapon was that it was less noisy when fired. It produced a short hissing sound, sort of like a pierced tire sound, not much like the usual gunshot noise. However, it earned its place in the history of small arms as one of the few rare examples of unconventional combat weapons that worked even a little.