Browning Hi-Power

The Browning Hi-Power is a single-action, 9 mm semi-automatic handgun. It is based on a design by American firearms inventor John Browning, and completed by Dieudonné Saive at Fabrique Nationale (FN) of Herstal, Belgium. Browning died in 1926, several years before the design was finalized. The Hi-Power is one of the most widely used military pistols of all time,[3] having been used by the armed forces of over 50 countries.[1]

The Hi-Power name alluded to the 13-round magazine capacity; almost twice that of contemporary designs such as the Luger or Mauser 1910. The pistol is often referred to as an HP (for "Hi-Power" or "High-Power")[4] or as a GP (for the French term, "Grande Puissance"). The term P-35 is also used, based on the introduction of the pistol in 1935. It is most often called the "Hi-Power", even in Belgium. It is also known as the BAP (Browning Automatic Pistol), particularly in Irish service.

The Hi-Power was designed in response to a French military requirement for a new service pistol, the Grand Rendement (French for "High Yield"), or alternatively Grande Puissance (literally "high power"). The French military's requirements were that the arm should be compact, have a capacity of at least 10 rounds, a magazine disconnect device, an external hammer, a positive safety, be robust and simple to disassemble and re-assemble, and be capable of killing a man at 50 meters; this last criterion was seen to demand a caliber of 9 mm or larger, a bullet mass of around 8 grams (123.5 grains), and a muzzle velocity of 350 m/s (1148 ft/s). It was to accomplish all of this at a weight not exceeding 1 kg (2.2 lb).

The pistols were originally made in two models: an "Ordinary Model" with fixed sights and an "Adjustable Rear Sight Model" with a tangent-type rear sight and a slotted grip for attaching a wooden shoulder stock. The adjustable sights are still available on commercial versions of the Hi-Power, although the shoulder stock mounts were discontinued during World War II. In 1962, the design was modified to replace the internal extractor with an external extractor, improving reliability.

Standard Hi-Powers are based on a single-action design. Unlike modern double-action semi-automatic pistols, the Hi-Power's trigger is not connected to the hammer. If a double-action pistol is carried with the hammer down with a round in the chamber and a loaded magazine installed, the shooter may fire the pistol by simply pulling the trigger. In contrast, a single-action pistol must be cocked manually before the first shot, either by thumbing the hammer back, or by pulling the slide to the rear and releasing it. In common with the M1911, the Hi-Power is therefore typically carried with the hammer cocked and the safety catch on (a carry mode often called cocked and locked in the USA or "made ready" in the UK, or sometimes called condition one).

The Hi-Power, like many other Browning designs, operates on the short-recoil principle, where the barrel and slide initially recoil together until the barrel is unlocked from the slide by a cam arrangement. Unlike Browning's earlier Colt M1911 pistol, the barrel is not moved vertically by a toggling link, but instead by a hardened bar which crosses the frame under the barrel and contacts a slot under the chamber, at the rearmost part of the barrel. The barrel and slide recoil together for a short distance but, as the slot engages the bar, the chamber and the rear of the barrel are drawn downward and stopped. The downward movement of the barrel disengages it from the slide, which continues rearward, extracting the spent case from the chamber and ejecting it. After the slide reaches the limit of its travel, the recoil spring brings it forward again, stripping a new round from the magazine and pushing it into the chamber. This also pushes the chamber and barrel forward. The cam slot and bar move the chamber upward and the locking lugs on the barrel reengage those in the slide.

The Hi-Power has two flaws: The standard trigger pull is heavy, especially for a single-action pistol. This disadvantage is a consequence of the Hi-Power's magazine safety design, which was initially added to the model to meet the requirements of the French military in 1935. The standard Hi-Power magazine safety is connected to the trigger and is released by a plunger pressing on the surface of the magazine. This action of the plunger on the magazine adds tension to the trigger pull, and the required force to operate this feature adds resistance as well. This problem is often resolved by removing the magazine safety entirely, thus voiding the pistol's warranty, or by polishing the interface surfaces between the safety plunger and the magazine.After-market trigger springs with reduced tension are also available to improve the trigger pull.

In addition, the pistol has a tendency to "bite" the web of the shooter's hand, between the thumb and forefinger. This bite is caused by pressure from the hammer spur, or alternatively, by pinching between the hammer shank and grip tang. Many HP owners fix this problem by altering or replacing the hammer, or by learning to hold the pistol to avoid injury. While a common complaint with the commercial models with spur hammers similar to that of the Colt "Government Model" automatic, it is seldom a problem with the military models, which have a smaller, rounded "burr" hammer, more like that of the Colt "Commander" compact version of the 1911.
Nevertheless, its ability to hold 13 rounds of ammunition, nearly double that of the Colt M1911 made it very desirable as a military-issue pistol.

Specifications of the Mk I

A locked-breech, semi-automatic, single-action, recoil-operated pistol. The Browning Hi-Power Mk I uses a 13-round staggered magazine.
Caliber: 9 mm
Length: 197 mm
Barrel length: 118 mm
length of rifled part: 100 mm
number of grooves: 6
direction of twist: right
Height (without sight, loaded): 127.5 mm
Width (with stocks): 36 mm
(without stocks): 25.5 mm
Weight (with empty magazine): 0.9 kg
(with loaded magazine): 1.060 kg
Capacity of magazine: 13 cartridges
Modes of fire: Single action
Muzzle velocity: 350 m/s
V12.50: 340 m/s
Muzzle energy: 500 J
Safeties: Half-cock notch, manual thumb safety, firing pin block, and magazine disconnect
Trigger pull: 7.5 lb
Effective Range: 50 m
Dispersion (firing 10 shots with rest)
at 15 metres: 95 mm (height 50 mm, width 45 mm)
at 30 metres: 200 mm (height 105 mm, width 95 mm)
at 50 metres: 320 mm (height 170 mm, width 150 mm)