One of the weapons developed during the early days of small-caliber high velocity research was a double-barreled .22 caliber FAL. This was a follow-on project to the modified T48 (American FAL test rifle) used to test the .22 HV featured in our last Weekly DTIC, itself tested alongside the .22 caliber M2 Carbine as part of the SALVO I Field Experiment. Unlike the earlier T48-based rifle, it fired a different, long-necked “duplex” variant of the .22 HV, with twin 41 grain bullets traveling at 3,250 ft/s. With this ammunition, the weapon could produce four high velocity projectiles with each pull of the trigger, giving it excellent dispersion and theoretically excellent hit probability at expected combat ranges (>300 yards). The disadvantages of an overly heavy weapon due to its twin barrels was not important, as it was intended as a test article only. At 11.8lbs unloaded, it was certainly heavy, though not as heavy as one might expect a twin-barreled semi-automatic rifle to be.

A Winchester cartridge board, showing several experimental military projects. The two cartridges in the middle of the middle row are .22 HV duplex rounds.

This rifle represents one of the earliest operational tests of the “hyper burst” concept. By the time of the ACR program in the late ’80s, this concept had fallen out of favor, as it was determined that while it did greatly increase the hit probability potential of the rifle, the errors induced by the shooter were the overwhelming contributor to misses in combat. Still, the promise of these burst-fire weapons was such that the SALVO, and later SPIW programs would continue trying to realize it in a package that was light, durable, and reliable enough for infantry use.

There is an excellent article on the Winchester SALVO rifle over at Gun Holsters & Gear, but some pics are also available below (image credits for the below images go to AR15.com user armeiro):

H/T to Daniel Watters for the article suggestion.