Semi-automatic handgun

A semi-automatic handgun is a small firearm most commonly used as a sidearm by police and military all over the world. It is often referred to as a mere pistol, although that term encompasses several other types of small firearm as well. Most types rely on a magazine which feeds ammunition through the hollow hand grip into the firing chamber. This allows for short reload times and larger number of bullets per loading than a revolver, at the cost of a more complex mechanism which may be prone to occasional jamming.

A semi-automatic weapon ejects the case and reloads the chamber automatically once the weapon is fired without additional action by the user. This is accomplished by gas pressure from the fired cartridge, which drives the breechblock backward, ejecting the spent case and forcing a new round to the chamber when it's pushed back forward by a spring. A semi-automatic will fire only one shot per pull of the trigger as opposed to an "fully automatic" which continues to fire until the trigger is released or all cartridges have been fired. While both types of weapons operate on the same principles, fully automatic weapons must be built more ruggedly to accommodate the heat and shock caused by rapid firing.

Semi-automatic pistols can be divided into "blowback" and "breechlock" pistols according to their principle of operation. In blowback pistols, the barrel is fixed to the frame and the breechblock, in its foremost position, is held against the barrel only by the force of the recoil spring. In breechlock pistols, the barrel is locked to the breechblock and recoils a short distance with it until it's unlocked by some mechanism, after which the breechblock continues its motion without the barrel. Blowback pistols are simpler in construct and thus cheaper to manufacture, but the blowback mechanism can only be used with cartridges of relatively low power. With high power cartridges the breech would open too quickly, unless the breachblock was made very heavy, leading the pressure to rupture the case which would thus fail to eject.

Another differing point among pistols are their trigger and ignition systems. Early designs use so called "single action" systems, where a hammer needs to be cocked to fire. When the trigger would be pulled, the hammer would drop, hit a firing pin which would strike the primer of the ammunition and fire the pistol. For carry the hammer would simply be blocked in its cocked position with a manual safety, these early designs could not prevent the pistol from firing if dropped on a hard surface as the firing pin was only being held in place by a spring. There was also a risk that such a pistol would fire in fully automatic mode if the spring retaining the firing pin would become to weak with use. In that case the pistol would start firing and only stop when it would run out of ammunition, posing a great risk for it user.

Later designs introduced the "double action" system, to fire simply remove the safety and pull the trigger and the hammer will raise and fall, hitting the firing pin. After the first shoot the system will revert back to single action, when the safety is applied the hammer falls back into a safe position and the firing pin is blocked so that the pistol will not fire if dropped on a hard surface. In most double action designs the trigger will be disconnected while the safety is applied. Note that some double action pistols lack the firing pin safety.

The newest designs use so called striker systems also called "safe action" or "semi-double action", there is no hammer and when one pulls the trigger one fully cocks the striker until it releases and fires the pistol. When the trigger is in ready position, the striker is blocked so that the pistol can not fire if dropped.

History

After Hiram Maxim introduced his recoil-powered machine gun in 1883, several gunsmiths set out to apply the same principle to handguns. The first model to gain any commercial success was the Borchardt self-loading pistol, designed by Hugo Borchardt and appeared in 1894. It featured a rather clever locking mechanism modelled after the human knee joint and proved mechanically reliable, but too large and bulky to be used comfortably by one hand. Equipped with a screw-on wooden stock it served well as small carbine, however. In 1896 Paul Mauser introduced his first model of the famous Mauser pistol. Using the powerful 7.36 mm bottle-necked cartridge originally designed for the Borchardt, the Mauser was the first semi-automatic pistol used extensively in battlefields, as in South African War of 1899-1902. The next notable design was the Luger Parabellum, featuring greatly improved Borchardt-type locking mechanism, by Georg Luger, which was adopted by the German military and served as their standard sidearm during World War I. During World War II Germany was the first nation to adopt a so called double action pistol, the Walther P38 which could be carried loaded and ready to fire at all times without the risk of an accidental discharge. Luger's 9 mm cartridge is the most widely used pistol cartridge today. In the United States, the first gun designer to develop self-loading pistols was John Browning, whose models were manufactured in Europe by the Belgian Fabrique Nationale and by Colt in the US. The .45 Colt 1911 was adopted by the US military and remained in service for over 70 years.

During World War II the only major powers to still resort to revolvers as sidearms were Britain, Russia and the United States. Though the British factory Webley and Scott had developed several adequate semi-automatic pistols, the British military preferred their trusty revolvers of the same manufacturer. In Russia the Nagant revolver remained the primary handgun because of a a lack of pistols. In the United States, both Colt and Smith & Wesson produced revolvers chambered for the same pistol ammunition as used in the Colt 1911, because of the great demand for handguns.

After WW2 most nations adopted 9mm Luger pistols for army use. The most popular being the FN Browning High-Power GP35, which was the first high capacity pistol, the other popular model was the Walther P38 beause of its many modern safety features. In 1972 Smith & Wesson was the first company to offer a safe double action high capacity pistol with its model 59. CZ launched its CZ-75 in 1975. Beretta its model 92 in 1976. SIG came up with the P226 not much latter and Glock introduced its ultra modern Glock-17 shortly afterwards.

After the second world war the semi-automatic pistols have replaced the revolvers used in the military and have also done so, although slightly more slowly, in police use. Today, revolvers are mainly found in the fields of civilian self-defence, hunting and target practice.

Famous semi-automatic handguns

The US, French and Italian military have adopted the Beretta 92. The British military and US Navy Seals the SIG-Sauer P226. The Austrian, Finnish and Norwegian military the Glock-17.

On a worldwide basis the Glock-17 and Glock-22 have become the most widely used law enforcement pistols.

Popular examples:

Luger (9mm Luger, 7.65mm Luger)
Glock Model 17 (9mm Luger)
Glock Model 22 (.40 S&W)
Glock Model 21 (45ACP)
Beretta 1934 (380ACP)
Beretta 92FS (9mm Luger)
Beretta 96 (.40S&W)
FN-Browning High Power GP35 (9mm Luger)
Colt M1911 (.45ACP, 38Super, 9mm Luger)
IMI Desert Eagle (357 Magnum, 44 Magnum, .50 AE)
Èeská Zbrojovka CZ-75 (9mm Luger, .40S&W)
SIG-Sauer P226 (9mm Luger, .40S&W)
SIG P210 (9mm Luger, 7.65mm Luger)
Smith & Wesson Model 39 (9mm Luger)
Smith & Wesson Model 59 (9mm Luger)
Smith & Wesson Model 5906 (9mm Luger)
Vis (9mm Luger)
DWM Luger P-08 (9 mm Luger)
Makarov (9mm Makarov)
Tokarev (7.63mm Russian)