The Olin Winchester Salvo Rifle,
During the 1950’s the US Military experimented with the concept of a Salvo rifle, a rifle that could increase the probability of hitting a target by firing multiple projectiles with one shot. Numerous prototypes were created which fired special duplex (two bullet) or triplex (three bullet) cartridges. The Winchester Salvo was one prototype based off of the FAL. An extremely bizarre weapon, the Winchester Salvo featured two barrels and two chambers which fired simultaneously. As a result, the Winchester Salvo used two magazines at once. While the Win Salvo was double barreled and fired both simultaneously, it only had one bolt with double extractors, and was operated with one gas system. It could be operated in semi automatic and fully automatic, and when fired the spent casings were ejected to the left and right.
To increase the Win Salvo’s firepower even further, the weapon used special 5.56 T65 Duplex ammunition. The T65 Duplex cartridge used 7.62 NATO brass, necked down to 5.56mm. However the Duplex cartridge featured two 35 grain or 41 grain bullets, with each seated on top of each other inside the cartridge. Thus when fired, the Duplex cartridge would fire two 5.56 projectiles at once. With the Winchester Salvo rifle, four projectiles would be fired with each trigger pull. Obviously when used in fully automatic fire, the Win Salvo sprayed a formidable stream of lead.
The bizarre Winchester Salvo produced by the Springfield Armory for US Army Ordnance testing. The Army rejected the design for a number or reasons. First and foremost the firing of two 5.56 T65 Duplex cartridges produced 25% more recoil than a .30-06 M1 Garand. The Win Salvo was also very heavy, weighing almost 12 pounds, 3 pounds heavier than the standard M14 battle rifle. Finally the Win Salvo was an ammo hog, firing two magazines worth of ammunition simultaneously. Remaining prototypes are currently on display at the Springfield Armory Museum.