The Browning Hi-Power is a single-action, semi-automatic pistol chambered for 9x19mm ammunition. Based on ideas John Moses Browning’s original work in 1922, the Hi-Power was completed by Dieudonne Saive working Fabrique Nationale (FN) of Herstal, Belgium who patented and produce the weapon.
Called ‘Hi-Power’ for its (at the time) remarkable magazine capacity rather than any special potency of the 9x19mm in this pistol. In its day the Hi-Power offered almost twice the number of shots compared to its contemporary service pistols, like the Luger and M1911. With the first functional double column magazine of 9x19mm, the Hi-Power was capable of holding 13 cartridges, for a total of 14 with one in the chamber. Over the years magazines with even higher capacities have been offered for the Hi-Power, today 15 round magazines are available that fit flush with the butt of the weapon, and protruding magazines of up to 20 rounds can be found.
Over its long history and many users, this pistol has carried a number of names, Hi-Power, High-Power and HP are common, as is GP (from the French "Grande Puissance" meaning High Power). P-35 is also a common name based on the year of its introduction (1935), so is GP-35 and FN is also used, somewhat loosely. Browning and Browning Automatic may be found in countries without any great exposure to JM Browning’s other pistols, in Ireland BAP (Browning Automatic Pistol) has been official terminology at some point.
A great source of this confusion arose from the manufacture of the this pistol by Inglis in Canada during WWII. While originally intended to be in 9x19mm, the engagement of Canadian forces in Northern Russia and Canada’s role in supplying Russian forces in the same theatre, led to the Hi-Power being re-chambered in 7.62x25mm for commonality. This version, officially known as the CP44 and informally as an Inglis, was picked up by FN after the war and offered along side their 9mm version. Further more FN had continued producing the original pattern all though the war for the Germans, and in the post war years the picture became very confused with many users operating both types together.
The origins of the GP-35 lay a French military requirement stemming out of WWI for a new service pistol. This specification called for 10 rounds of a cartridge capable of killing a man at 50m in an arm that was compact, robust and simple, with magazine and manual safety, and an external hammer, all at a weight not to exceed 1kg (2.2lb).
Browning was commissioned by his long time affiliate FN to design a weapon to this specification and found himself forced to start from scratch due to having sold his principal locked breech pistol patents to Colt with the M1911. He designed a number of prototypes in 9mm to meet the lethality requirement, eventually leading towards a striker-fired locked-breech design with a staggered double column magazine to hold 16 rounds without undue bulk. Despite not having the external hammer called for in the original requirement, this pistol, the Grand Rendement ("High Yield"), was refined and subject to a series of trials Versailles Trial Commission in France.
Browning died in 1926 without having finished his new pistol and FN handed the project over to Dieudonne Saive. In 1928 the key patents held by Colt for the M1911 expired, and Saive incorporated many of the proven elements from this design back into Brownings new work to produce the Saive-Browning Model of 1928.
This model was further refined, in 1931 the magazine and grip were shortened to 13 rounds and the grip itself given a more rounded back strap, while internally the barrel bushing was changed from a detachable M1911 type to one integral with the slide. Four years later the pistol was ready, adopted by Belgium as the Browning P-35 and offered for commercial sale as Grande Puissance (literally "high power"). France opted to adopt an alternative design, the Mle.1935 which was founded closely on Browning’s work but developed by Charles Petter a Swiss.
Since then FN has revised the GP-35 many times and offered it many forms, most notably the pre-war de lux version provided with a 500m adjustable tangent sight and detachable holster-stock. Today the basic GP-35 is still available in a form essentially unaltered from the original military specification, with only neoprene grips, an ambidextrous safety and higher profile sights as the visible changes.