Savage Hi-Power aka 5.6×52mmR cartridge was created by Charles Newton and produced by Savage Arms in 1912. It is also known as the .22 Savage High-Power and .22 “Imp”, and is based upon the .25-35 Winchester cartridge necked down to accept a .227in/.228in diameter bullet. Its original loading was a 70 grain soft point bullet with a velocity of around 2700–2800 feet per second depending on the rifle.
Its relatively high velocity for the time and “shocking” power led to an initial surge of popularity, and the “Imp” was attributed with almost magical killing powers even on large and dangerous soft-skinned game such as tigers. Reverend H. R. Caldwell used his .22 Hi-power on 400 pound tigers in China with success, something the Savage rifle company exploited in its advertising for the cartridge in the early days. The famous elephant hunter WDM Bell used a .22 Savage Hi-Power to kill Cape buffalo in West Africa in the 1920s, and reported in his magazine articles that the cartridge was popular at that time for red deer stalking in Scotland. While it was used in the UK on deer as large as Red Stags, it fell out of favour as a big game cartridge due to its small caliber and light bullets. Other .22 Centrefires cartridges outstripped it in performance such as the .220 Swift, and after the 1950s, with the advent of the .222 Remington, the cartridge was considered obsolete. Today it is regarded as a vintage round, and aficionados use it for small game hunting in similar applications as the .222 and the .223 Remington; although it is used for deer hunting where it is legal to do so. In Europe the cartridge is still chambered in combination guns, and the cartridge is still used by hunters for smaller European deer species such as Roe deer.
No ammunition or mass-market rifle-making company in the U.S. produces the .22 SHP as of 2007, either as a cartridge or a factory chambering. Norma, Sellier & Bellot, and Wolf Ammunition (through their “gold” line) still manufacture ammunition for the European market, and export it to the U.S. In the 5.6×52mmR designation this cartridge remains significant among hunters in Europe, where it is often a chambering in drillings and similar combination guns.