Olin/Winchester Salvo Rifle
Country of origin

United States




Stefan K. Janson

Production began


Weapon type

Assault rifle


5.56mm T65 Duplex



Overall length

1105mm (43.5 in)

Barrel length

584mm (23 in)


4.4kg (11.8 lbs)

Magazine/Cylinder capacity

40 rounds (20 in each detachable box magazine)

Cyclic rate

1300 to 1400 RPM (per barrel)
2600 RPM (both barrels)

Muzzle velocity

3,505 fps

The Olin/Winchester Salvo Rifle is an experimental double-barreled 5.56mm automatic rifle created for the U.S. Army's Project SALVO in the 1950s.

Developed in hopes of increasing the hit probability of soldiers in combat, the Salvo Rifle was designed by Stefan K. Janson, who had previously created the Enfield EM-2 bullpup rifle for the British Army.

Design DetailsEdit

The Salvo Rifle design appears to be a pair of FN FAL rifles grafted together, sharing a single gas system. The Salvo Rifle was chambered for the experimental 5.56mm T65 Duplex cartridge, based on a long-necked variant of the 7.62×51mm NATO cartridge case loaded with a pair of conventional projectiles. Two variants of the duplex cartridge existed: one fired two 35 grain projectiles at 3,505 fps, while the other fired a pair of 41 grain bullets at 3,250 fps. With its two barrels each firing a duplex cartridge, the Salvo Rifle would effectively launch four projectiles with every press of the trigger. However, this proved to be the Salvo Rifle's downfall as the recoil of firing two duplex cartridges at the same time exceeded that of the M1 Garand.

An example of the Salvo Rifle is currently held in the collection of the Springfield Armory Museum.