The.345 Winchester Self-Loading (.345 WSL / .345 Winchester Machine Rifle) or8.8x34mm WSL is a rimless, rifle cartridge in a "cylindrical" shape, created in 1917 by theWinchester Repeating Arms Company.[1]
It was designed by Frank F. Burton for theWinchester-Burton Machine Rifle, also known as the Winchester Model 1917.[2] While few original documents pertaining to the rifle have survived, it was probably intended primarily for use as an anti-balloon weapon,[1][3] while fitted to aircraft. However, an alternate barrel with a bayonet attachment, for use by infantry, was also designed.
During the outbreak of the First World War, observation balloons were essential for both sides of the front.[4] These static balloons inflated with hydrogen, became targets for airmen on both sides, and were defended by anti-aircraft batteries and patrol fighters.[5]
To face these balloons, conventional ammunition proved to be inefficient, and other alternatives were sought.[6] In 1916, French officer Yves le Prieur created a rocket system powered by electricity, but its range was limited. In 1917, tracer and incendiary ammunition was being developed to target these balloons.[1][5]
To meet this need, Frank F. Burton of Winchester, developed the "Burton Light Machine Rifle", a selective fire blowback rifle, with selection of rate of fire to be used in observation and surveillance planes, the first practical version of which was ready in 1917.[7][8][9] For this rifle, he adapted the .351 WSL cartridge into a rimless cartridge, firing an incendiary Spitzer bullet, resulting in the .345 Winchester Self-Loading.[1][10]