Big Joe 5 crossbow

The Big Joe 5 crossbow (BJ5) was a shoulder-fired weapon developed by the Office of Strategic Services (OSS) (predecessor to Central Intelligence Agency) to be used for assassinations up to 200 m (220 yd).^[1] The weapon was created with compactness in mind. It is described in John Brunner's book OSS Weapons.^[2] Its ammunition consisted of 8 oz (230 g) aluminum darts or incendiary flare bolts.^[3]

Unlike most crossbows, the Big Joe 5 used a rigid triangular frame to suspend an array of elastic rubber bands, which provided the energy storage and propulsive mechanism for the bolts.^[4] The body of the weapon was roughly the size of a large handgun and it featured a hinged stock of heavy steel wire that doubled as a cocking lever. For transport and concealment the frame and stock could be folded, resulting in a very compact package.