Semi-automatic rifle

A semi-automatic rifle is an auto-loading rifle that fires a single round of ammunition at a time. It uses part of the fired cartridge's energy to eject the case and automatically loads another cartridge into its chamber. This is in contrast to bolt-action or lever-action rifles, which require the user to manually chamber a new round before they can fire again, and fully automatic rifles, which fire continuously while the trigger is held down.

Ruger 10/22 - .22 Long Rifle

SKS Type 56 - 7.62×39mm

Colt AR-15 SP1 - .223 Remington

Drawing of the Mannlicher 1885 semi-automatic rifle by Ferdinand Mannlicher, one of the earliest semi-automatic rifle designs.

Prague Castle Guard carrying the Czechoslovak vz. 52 rifle

History

In 1883, Hiram Maxim patented a recoil-operated conversion of a Winchester rifle. Another of the first designs of a recoil-operated semi-automatic rifle is attributed to Ferdinand Mannlicher, who unveiled his design in 1885 based on work begun in 1883. Other non-gas-operated models included the Mannlicher Model 85, 91, 93, and 95 rifles. The designs never proceeded past the conceptual/prototype stage due to issues inherent to the black powder used in their cartridges (based around the Austrian 11×58mmR M/77), such as insufficient velocity and excessive fouling. Automatic firearms would only become feasible after smokeless powder became widespread. Mannlicher's designs served as a basis for multiple other firearms, such as Browning machine guns (M1917, M1919, and M2). Mannlicher produced smokeless powder versions of his guns, beginning in the early 1890s, until he died in 1904.

The Fusil Automatique Modele 1917 was an early French semi-automatic rifle issued in limited numbers to the French Armed Forces during World War I.

Blowback semi-automatic

In 1903 and 1905, the Winchester Repeating Arms Company introduced the first low-power blowback (shell-operated) semi-automatic rifles firing rimfire and centerfire ammunition. The Winchester Model 1903 and the Winchester Model 1905 operated on the principle of blowback to function semi-automatically. Designed by T.C. Johnson, the Model 1903 achieved commercial success and continued to be manufactured until 1932, when the Winchester Model 63 replaced it.

By the early 20th century, several manufacturers had introduced semi-automatic .22 rifles, including Winchester, Remington, Fabrique Nationale, and Savage Arms, all using the direct blowback system of operation. Winchester introduced a .351 Winchester Self-Loading semi-automatic rifle, the Model 1907, as an upgrade to the Model 1905, utilizing a blowback system of operation, offering more power than its .22 counterpart. Both the Model 1905 and Model 1907 saw limited military and police use.

Early semi-automatic rifles

In 1883, Officer of Artillery Willhelm H. O. Madsen and intendant of the arms factory in Copenhagen, Julius A. N. Rasmussen (last name later changed to Bjarnov), began developing recoil-operated, self-loading firearm designs. By 1887, they had created a functional prototype, which was later designated the "M1888 Forsøgsrekylgevær." The Danish military tested this rifle but ultimately rejected it for military adoption. Following the unsuccessful trials, the pair developed a new design, known as the "M1896 Flaadens Rekylgevær.". This model was also tested by the Danish military, and this time it was found to be reliable. As a result, 60 units were procured for the Danish Navy, making it one of the earliest semi-automatic rifles to be officially adopted by a military force.

In the final years of the 19th century and early 20th century, experiments and patents with gas-operated reloading were developed by Hiram Maxim and Richard Paulson as well as a gas-operated conversion system from an American inventor named Henry Pitcher. Other designs were also developed, such as the Cei-Rigotti in 1900.

In 1906, Remington Arms introduced the "Remington Auto-loading Repeating Rifle." Remington advertised this rifle, renamed the "Model 8" in 1911, as a sporting rifle. It was sold in Europe by FN Herstal as the "FN Browning 1900". The rifle is a locked breech, long recoil action designed by John Browning, and was offered in .25, .30, .32, and .35 caliber models. In 1936, the Model 81 superseded the Model 8 and was offered in .300 Savage as well as the original Remington calibers.

In 1908, General Manuel Mondragón patented the Mondragón rifle, designated the M1908. The rifle was used by Mexican forces in the Mexican Revolution, making Mexico the first nation to use a semi-automatic rifle in battle, in 1911.

The M1 Garand was designed by John Garand in 1936 and initially produced for the United States military.

Shortly after the Mondragón rifle was produced, France had its own semi-automatic rifle, the Fusil Automatique Modele 1917. It is a locked breech, gas-operated action that is similar in its mechanical principles to the subsequently manufactured American M1 Garand. However, its shortened and improved version, the Model 1918, was used more during the Moroccan Rif War from 1921 to 1926. Still, the bolt-action Lebel Model 1886 rifle remained the standard French infantry rifle until being replaced in 1936 by the MAS-36, another bolt action, despite the various semi-automatic rifles designed between 1918 and 1935.

Other nations experimented with self-loading rifles during the interwar period, including the United Kingdom, which had intended to replace the bolt-action Lee–Enfield with a self-loading rifle, but this plan had to be discarded when the Second World War became imminent, shifting its emphasis to speeding up re-armament with existing weapons.

Gas-operated rifles

M1941 Johnson rifle Semi-Automatic Rifle with original spike bayonet and leather sheath. The 10-round rotary magazine could be quickly reloaded using two clips of .30 Caliber M2 Ball ammunition.

In Springfield, Massachusetts, John Garand, a Canadian-born firearms designer, was tasked with designing a basic gas-actuated self-loading infantry rifle and carbine that would eject the spent cartridge and reload a new round using a gas-operated system. Designing a rifle that was practical in terms of effectiveness, reliability, and production was difficult, and it took fifteen years to perfect the M1 prototype model to meet all the U.S. Army specifications. The resulting Semi-Automatic, Caliber .30, M1 Rifle was patented by Garand in 1932, approved by the U.S. Army on January 9, 1936, and went into mass production in 1940. Thus, in 1936, the American M1 Garand rifle became the first gas-operated semi-automatic rifle to be adopted by a country as their standard-issue service rifle. General George S. Patton described the M1 Garand as "the greatest battle implement ever devised." It replaced the bolt-action M1903 Springfield and became the standard infantry rifle known as the Garand Rifle. During World War II, over 4,000,000 M1 rifles were manufactured.

The Soviet AVS-36, SVT-38, and SVT-40, as well as the German Gewehr 43, were semi-automatic gas-operated rifles issued during World War II in relatively small numbers. In practice, they did not replace the bolt-action rifle as a standard infantry weapon of their respective nations—Germany produced 402,000 Gewehr 43 rifles, and over 14,000,000 of the Kar98k.

Another gas-operated semi-automatic rifle developed toward the end of World War II was the SKS. Designed by Sergei Gavrilovich Simonov in 1945, it came equipped with a bayonet and could be loaded with ten rounds, using a stripper clip. It was the first widely issued rifle to use the 7.62×39mm cartridge. By the end of World War II, however, semi-automatic rifles had been largely superseded in military usage by their fully automatic and select-fire counterparts - weapons such as the AK-47, FN FAL and M16 limited the viability of widespread deployment of semi-automatic rifles.

U.S. Marine with a Barrett M82

Gradually, military doctrine evolved to place less emphasis on individual marksmanship, as a large volume of fire was deemed more important – during World War II, American ground forces fired approximately 25,000 rounds for each enemy killed. In the Korean War, this number increased to 50,000, and in the Vietnam War, it became 200,000 rounds per enemy. The first fully automatic rifle to see widespread usage was the German StG 44, which was reportedly well-liked by troops, as the 30-round selective fire rifle gave them much more flexibility than their service rifle, the bolt action Karabiner 98k.

Ultimately, automatic rifles would become standard in military usage, as their firepower was superior to that of a semi-automatic rifle. However, both semi-automatic and bolt action rifles are still widely used today in military service in specific roles, such as designated marksman rifles where the greater accuracy compared to automatic rifles is valued. Furthermore, to accommodate for this greater firepower, battle rifles were mostly replaced by assault rifles, whose lighter bullets allowed more ammunition to be carried at once. Where semi-automatic rifles continue to be used, they are usually in higher calibers, such as the .50 BMG Barrett M82.

Operation

SIG Sauer MCX

Semi-automatic weapons use gas, blow-forward, blowback or recoil energy to eject spent cartridges after the round has moved down the barrel, to chamber a new cartridge from the weapon's magazine, and to reset the action. This enables another round to be fired once the trigger is depressed again.

Semi-automatic rifles can be fed by an en-bloc clip, external magazine, or stripper clip.

Ruger AR-556.

The self-loading design was a successor to earlier rifles that required manual cycling of the weapon after each shot, such as the bolt-action rifle or repeating rifles. The ability to automatically load the next round results in an increase in the rounds per minute the operator can fire.

Advantages

The main advantage of semi-automatic rifles is their ability to fire multiple sequential shots quickly because avoidance of manually chambering cartridges allows maintaining the aiming position. Engaging a single target multiple times rapidly or multiple targets rapidly, greatly increases the effectiveness of a firearm in most applications. Semi-automatic rifles can typically more than double the hits at close range and increase hits by about 50% at longer distances compared to manually loaded rifles. The added weight of springs and fittings in self-loading mechanisms, along with some of the cartridge energy being used to reload, can give the advantage of reduced recoil. Reduced recoil helps keep the rifle on target for successive shots, improving overall accuracy.

Disadvantages

A self-loading mechanism, tuned for specific cartridge dimensions and power, may fail to reload dirty or bent cartridges that would otherwise fire. It can also struggle to extract low-power training cartridges or may be damaged by high-power rounds. Some rifles require lubricated cartridges, making them prone to collecting dirt. Reliability issues in the mechanism can negate the advantage of faster firing, potentially lowering the rate of fire compared to manually loaded rifles if not designed for easy manual reloading. The United Kingdom regarded the reliable rate of fire from manually loaded rifles to be nearly as high as self-loading rifles as recently as World War II.

Semi-automatic rifles are uniquely susceptible to slamfire malfunctions caused by abrupt cartridge acceleration during self-loading. Slamfire discharges are unlikely to hit the target and may cause collateral damage.

The time required for changing or reloading magazines can weaken the effectiveness of a rifle, as it imposes an effective duration limit on the continuous rate of fire of any rifle. High-capacity magazines increase the weight of the rifle and typically reduce feeding reliability due to the varying spring tension from a full to a nearly empty magazine. Detachable magazines in general are usually less durable than internal magazines.

The complexity of a self-loading mechanism makes self-loading rifles more expensive to manufacture and heavier than manually loaded rifles. The semi-automatic M1 Garand weighs about 410 grams (0.9 lbs) more (around seven percent) than the manually loaded M1903 Springfield it replaced. American development of a self-loading infantry rifle began with the .276 Pedersen cartridge in recognition of the difficulties of producing reliable self-loading mechanisms for more powerful cartridges. Although the M1 Garand was ultimately adapted to fire the .30-06 Springfield cartridge at the insistence of General Douglas MacArthur, most subsequent self-loading rifles for infantry use have been chambered for less powerful cartridges to reduce weight, making the service rifles easier to carry.

Select examples

• Mondragón rifle
• Mauser M1916
• M1917 RSC
• M1922 Bang rifle
• General Liu rifle
• M1 Garand
• Type 4 rifle
• SKS
• Dragunov Rifle
• Gewehr 43
• SVT-40
• Ag m/42
• Hakim rifle
• Rasheed Carbine
• AR-10
• AR-15
• L1A1 Rifle
• Heckler & Koch PSG1
• Heckler & Koch SL8
• Heckler & Koch SL7
• Heckler & Koch SL6
• Farquhar-Hill Rifle
• Kbsp wz. 1938M
• M1 Carbine
• Springfield Armory M1A
• Ruger Mini-14
• M1941 Johnson rifle
• Gewehr 41
• vz. 52 rifle
• MAS-49 rifle
• FN Model 1949
• Ruger 10/22
• Marlin Model 60
• Remington Model 7400
• Remington Model 8
• Winchester Model 1907
• Walther WA2000
• ZH-29
• Smith & Wesson M&P15-22

Civilian uses for semi-automatic rifles

Sport shooting

Target shooting has a long history, predating the firearm. As weapons that demanded user accuracy developed, so did their usage in competitions. Today, semi-automatic rifles are one of the more prominent firearms in sport shooting. There are various types of sport shooting, ranging from rapid-fire shooting; target shooting, which is predominantly accuracy based; and distance shooting. Shooting clubs in America became increasingly commonplace in the 1830s, and have since grown in popularity. Semi-automatic rifles are used in various sport shooting events, including target shooting and rapid-fire competitions, which has invited more people, specifically women and children, to compete as well.

Hunting

Semi-automatic rifles have grown in status among hunters. Some hunters use semi-automatic rifles, including AR-15 style models, citing their compact design and customisation options, effectively making it easier to traverse rugged terrain while tracking a target and providing a large variety of customization ranging from scopes and muzzle devices, to different calibers. Semi-automatic fire greatly assists in maintaining one's sight picture, which is especially important when follow-up shots are required. Due to their demand, the manufacturers of semi-automatic firearms have greatly increased the effective firing distance of their products compared to the first semi-automatics sold on the civilian market.

Self defense

Semi-automatic rifles are sometimes used for self-defense. Most semi-automatic rifles are rather lightweight and simple to operate, without compromising accuracy. Range-adjustable sights are also common, allowing their use in different environments.

See also

• Assault rifle (not to be confused with "Assault weapon")
• Assault weapon - certain semi-automatic rifles are classified as assault weapons in some jurisdictions
• Firearm
  • Pistol
  • Revolver
  • Semi-automatic pistol
• AR-15 style rifle
• Personal defense weapon
• Rifle
  • Automatic rifle
  • Bolt-action rifle
• Semi-automatic firearm
  • Semi-automatic pistol
  • Semi-automatic shotgun
• Shotgun
• Single-shot
• List of semi-automatic rifles

References

Johnson, Melvin M. (1944). Rifles and Machine Guns. New York: William Morrow and Company.

External links

• Early Semi-Automatic Rifles