This old North American cartridge was designed by Charles Newton and commercialized by Savage in 1912. The .22 High-Power is based on the old .25-35 Winchester case necked down to accept .227-.228 inch bullets. Reloaders should note the odd bullet size; the .22 High-Power does not use standard .224" (5.56mm) diameter bullets. It is unusual in being a .22 that was designed as a combination varmint and deer cartridge.
The High-Power had a run of popularity in North America starting back before World War I, but the cartridge got a reputation as a wounder of deer. Eventually American shooters went back to larger caliber cartridges for deer hunting, and the .22 High-Power fell into disuse and eventual obsolescence.
The .22 High-Power retains a modest level of popularity in Europe where its rimmed case makes it adaptable to the break action combination guns and drillings beloved in the Old World. In Europe the High-Power is called the 5.6x52R because it uses a 5.6mm bullet in a rimmed case 52mm in length.