Winchester introduced their .22 Winchester Automatic cartridge in 1903 for their Winchester Model 1903 semi-automatic rifle. There were no other firearms built to fire this cartridge during that time or since. The case itself is slightly thicker and longer than similar rimfire cartridges. This was done intentionally so that rifles in this caliber could not accept other .22 rimfire cartridges. This is because most .22 caliber cartridges of the time were charged with black powder, and residue from black powder cartridges would quickly render the action of the Model 1903 inoperable.
The .22 Winchester Automatic performs much like a .22 Long except that the bullet is heavier. There is no overall performance gain with the .22 Win Auto over the .22 Long. The muzzle velocity of the .22 Win Auto 45 grain LRN bullet is about 1,000 feet per second, and the muzzle energy barely exceeds 100 foot pounds.
Winchester reworked their Model 1903 to accept the .22 Long Rifle cartridge in 1932. This effectively displaced the .22 Winchester Automatic from the shooting sports industry and soon it was obsolete. Since that time, the ammunition has been produced a few times in small batches, the latest run coming from Aguila.
The .22 Winchester Automatic is not really a great round for hunting, and its limited availability reduces the chances that it will be used for plinking, but the cartridge is interesting for collectors of both ammunition and Winchester products.