The .22 ILARCO / 5.7x24mmRF, also known as the .22 Winchester American Magnum Special, .22 Winchester Short Magnum Rimfire, or .22 American,Barnes, F. C., & Woodard, W. Todd. (2016). Cartridges of the world, 15th edition: A complete and illustrated reference for more than 1500 Cartridges. Gun Digest. was a rimfire cartridge designed in 1987 for the American-180 rimfire submachine gun. At the time the cartridge was created, the design of the American-180 had been taken over by the Illinois Arms Company, Inc., hence the ILARCO name.22 ilarco. International Ammunition Association Web Forum. (2015, October 18). https://forum.cartridgecollectors.org/t/22-ilarco/16730/21
History Sometime after the Illinois Arms Company, Inc. (ILARCO) purchased the rights to the American-180 they determined a more powerful cartridge would be appropriate, which resulted in the creation of the .22 ILARCO. The new cartridge was designed so that a simple change of barrel was all that was required to switch between standard .22 Long Rifle, for which the gun was designed, and the new cartridge.
Dimensions and loading The .22 ILARCO uses a shorter version of the .22 Winchester Magnum Rimfire case, which use the same projectile as the original .22 Winchester Magnum Rimfire cartridge.
See also 5 mm caliber List of rimfire cartridges
References