Rare guns you have never heard of

Is there such a thing as a rocket gun? Welcome to the world of the Gyrojet.

Robert Mainhardt, an engineer at Los Alamos, designed the Gyrojet alongside business partner Arthur Biehl, hoping to create an anti-personnel rocket weapon. Think of it as a rocket launcher scaled down to the size of a rifle or even a pistol. The weapon fired steel-tipped rockets designed to pierce armor, stabilized in flight by ported exhaust tubes that provided aerodynamic spin.

Unfortunately, the Gyrojet experienced problems as soon as it left the lab. The rounds were too slow to have stopping power upon leaving the barrel. Although the rockets eventually exceeded Mach 1, the slow start meant it was useless at most ranges. Other drawbacks, such as the rockets' low tolerance for humidity, doomed the Gyrojet.

Today, it is an expensive collector's piece. It is most famous for being featured in the James Bond movie You Only Live Twice.