Semi-automatic rifle

A semi-automatic rifle is a type of self-loading rifle (also called auto-loading rifle) whose action will automatically cycle (ejects and rechambers) a new round after each shot, but needs the shooter to manually release the trigger and reset/recock the sear and hammer/striker before pulling again to fire another shot; thus, only one round is discharged with each pull of the trigger.

In contrast, a fully automatic rifle both cycles the cartridges and cycles (resets and releases) the hammer/striker automatically (the trigger merely keeps the sear disengaged), so for the duration of the trigger-pull the gun will fire rounds continuously until the ammunition is depleted, or until the trigger is released.


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

Semi-automatic rifles can be efficiently fed by an en-bloc clip and internal magazine, a detachable magazine, or a combination of stripper clip and internal magazine.

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.


The chief advantage of self-loading rifles is the possibility of increasing the number of effective shots fired within any given time period by avoiding the necessity for changing the aiming position of the rifle to manually chamber new cartridges. The actual number of hits per unit of time depends upon the magazine capacity and the availability of detachable magazines, but semi-automatic rifles can typically more than double the number of hits from comparable manually-loaded rifles at close range and increase the number of hits by about 50 percent at longer distances requiring more precise aiming. Firing for prolonged periods may increase this advantage if the manual-loading process causes shooter fatigue. The additional weight of springs and fittings using a portion of the cartridge energy to reload self-loading rifles have the additional advantage of reducing recoil.[1]


The self-loading mechanism tuned for cartridges of specified dimensions and power may fail to reload dirty or bent cartridges that will otherwise fire satisfactorily. The self-loading mechanism may fail to extract empty low-power cartridge cases useful for training, and high-power cartridges useful at longer ranges may damage the self-loading mechanism. Some self-loading rifles require externally lubricated cartridges vulnerable to dirt adhesion. Failure of the self-loading mechanism to function as designed eliminates the advantage of increased hits per unit of time, and may actually reduce the comparative rate of fire below what is possible with manually-loaded rifles if the self-loading rifle is not designed for convenient manual-loading. 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.[2]

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.[3]

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 seven percent more than the manually-loaded M1903 Springfield rifle it replaced. United States development of a self-loading infantry rifle began with the .276 Pederson cartridge in recognition of the difficulties of producing reliable self-loading mechanisms for more powerful cartridges. Although the Garand was ultimately adapted to fire the .30-06 Springfield cartridge at the insistence of General Douglas MacArthur,[4] most subsequent self-loading rifles for infantry use have been chambered for less powerful cartridges to reduce weight making rifles easier to carry.


The time required for changing or reloading magazines must be considered whenever the number of shots fired exceeds the magazine capacity imposing an effective duration limit on whatever rate of fire can be sustained from any rifle. High-capacity magazines increase the weight of the rifle, and typically reduce reliability due to the varying spring tension from full to a nearly empty magazine. Detachable magazines in general are usually less durable than internal magazines.


The first successful design for a gas operated semi-automatic rifle is attributed to Ferdinand Mannlicher, who unveiled the design in 1885.[5] Other non-gas operated semi-automatic models were the Model 85 and Mannlicher Models 91, 93 and 95 rifles.[6]

Blowback semi-automatic

In 1903 and 1905, the Winchester Repeating Arms Company introduced the first low-power blowback (non-gas operated) semi-automatic rimfire and centerfire rifles. The Winchester Model 1903 and 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 blow-back system of operation. Winchester introduced a medium caliber semi-automatic rifle, the Model 1907, as an upgrade to the Model 1905, utilizing a blowback system of operation, in calibers such as .351 Winchester. Both the Model 1905 and Model 1907 saw limited military and police use.

Early semi-automatic rifles

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. This is a locked-breech, long recoil action designed by John Browning. The rifle was offered in .25, .30, .32, and .35 caliber models, and gained popularity among civilians as well as some law enforcement officials who appreciated the combination of a semi-automatic action and relatively powerful rifle cartridges. 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 Mondragon patented the world's first gas-operated semi-automatic rifle, the Mondragón rifle M1908. Mexico was to the first nation to use a semi-auto rifle in battle in 1911; the rifles were issued to regular troops during the Mexican revolution. This would be the basis of all future semi-automatic firearms to date.

After the Mondragon rifle was released, France came out with its own semi-automatic rifle, the Fusil Automatique Modele 1917. This is a locked breech, gas-operated action which is very similar in its mechanical principles to the subsequent M1 Garand in the United States. The M1917 was fielded during the latter stages of WWI, where it did not receive a favorable reception. However its shortened and improved version, the Model 1918, gave complete satisfaction during the Moroccan Rif War from 1920 to 1926. Still, the Lebel bolt-action rifle remained the standard French infantry rifle until replaced in 1936 by the MAS-36, also a bolt action, despite the various semi-automatic rifles designed between 1918 and 1935.

Other nations experimented with self-loading rifles between the two World Wars, including the United Kingdom, which had intended to replace the bolt-action Lee–Enfield with a self-loading rifle, The UK discarded that plan when the Second World War became imminent, shifting its emphasis to speeding-up re-armament with existing weapons. The Soviet Union and Nazi Germany both issued effective self-loading and selective-fire rifles on a large scale during the course of that war, but not in sufficient numbers to replace their standard bolt-action rifles.

Gas-operated rifles

In 1937, the American M1 Garand was the first semi-automatic rifle to replace a nation's bolt-action rifle as the standard-issue infantry weapon. The gas-operated M1 Garand was developed by Canadian-born John Garand for the U.S. government at the Springfield Armory in Springfield, Massachusetts. After years of research and testing, the first production model of the M1 Garand was unveiled in 1937. During World War II, the M1 Garand gave American infantrymen an advantage over their opponents, most of whom were issued slower firing bolt-action rifles.[7]

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.

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.[8]

Select examples

Semi-automatic rifles vs automatic rifles

Modern semi-automatic rifles are commonly mistaken for Assault Rifles; assault rifles, per political definition, have fully automatic firing capabilities and high capacity magazines. Semi-automatic rifles, while they may look similar to fully automatic rifles, are not the same, and automatic rifles are already illegal in the United states to civilians. One of the most popular semi-automatic rifles in the United States is the AR-15[9]. The “A-R” stands for Armalite Rifle, not assault rifle or automatic rifle, and is commonly mistaken for and identified as an assault rifle. Assault rifles are defined as “a rapid-fire, magazine-fed automatic rifle designed for infantry use” per the Oxford dictionary[10]. While some variations of semi-automatic weapons have superficial features which can resemble an assault rifle in some cases, they are not one in the same weapons and do not have the same capabilities. Assault rifles, or machine guns, are already illegal to be manufactured and sold for civilian use in the United States[11]. Fully automatic weapons have been under strict law to the public since 1986, are only available for purchase in the United States used, are heavily regulated by the ATF, and take an enormous amount of time and money to obtain[12]. While there are vast differences between fully automatic and semi-automatic rifles, it doesn't stop semi-automatic rifles from being in the heat of debate. There are over 160 different types of semi-automatic rifles available to the public, and the biggest distinguishing factor between different types of rifles is their outward appearance. Typically, when showed two rifles, similar in velocity, rate of fire, magazine capacity, ammunition, firing capabilities, and range, but with different exterior styles, black versus the wooden, the black semi-automatic rifle is chosen to be considered the assault weapon, nearly every time; the wooden semi-automatic rifle, is thought to be the less invasive, hunting rifle rather than a killing rifle, unlike the semi-automatic rifles that are black or metal.

Semi-automatic rifles and gun violence in the U.S.

Semi-automatic rifles have a bad reputation, mostly due to their misused names and aggressive appearance, only make up less than 5% of homicides in the United States per year; this includes both semi-automatic rifles as well as standard rifles, making the homicide rate of semi-automatic rifles less than 5%. Since 1999, there have been a total of 115 mass shooting defined by the media as, a shooting taking place in a public place where four or more people, not including the shooter, were killed by a gun[13]. Of the 115 mass shootings in the United States from 1999 to September 2019, semi-automatic rifles were only used in 32 of them. Studies do suggest however, that when semi-automatic rifles are used, particularly in a mass shooting, the number of casualties in a single incident does tend to increase. The 2017 Las Vegas shooting for instance, which is the deadliest mass shooting in America to date, was largely carried out by semi- automatic rifles[14]. While the number of casualties in a single incident may be higher when a semi-automatic rifle is used, handguns make up more than 64% of all gun related murders in the United States.

Civilian uses for semi-automatic rifles.

Semi-automatic rifles have been available for civilian use in America since the early 1900’s, and have grown in popularity since then. Semi-automatic rifles are most commonly used in civilian America for sport shooting, hunting, and self-defense against home invasions.

Sport shooting

Shooting at targets to improve accuracy began before guns, and started with bows and arrows. While target shooting was first introduced as practice, typically to soldiers and warriors, with bows and arrows before the invention of guns, it later evolved into sports such as target shooting, sport shooting and marksmanship. Target shooting, or practicing, progressed with the introduction of guns into society in the 1700's, primarily due to the lack of aim in war, such as the Civil War, and has evolved into sports of all kinds. Today, semi- automatic rifles, are one of the more popularly used weapons in sport shooting. There are many different types of shooting for competition ranging from rapid fire shooting, target shooting, which is accuracy based, and distance shooting. Shooting clubs in America came about in the 1830's[15], and have since grown in popularity. Semi-automatic rifles are commonly used in some sport shooting events because of their accuracy, versatility, and their lightweight, which opens the doors for more people, such as women, to compete as well.


Semi-automatic rifles are also growing in status among hunters. Many hunters are turning towards semi-automatic rifles to take on their hunting trips because of their features; these features include compactness, which makes it easier to climb through rugged terrain in a safer matter, the semi-automatic feature which gives hunters the ability to stay in a shooting position after firing, versus having to reload after every shot allowing for a swifter, more efficient kill, resulting in less of chance for an injured animal to get away[16]. Semi-automatic weapons also have increased the distance they can shoot, without giving up accuracy or power, again ideal for huntsmen. These features have been ground breaking in the sport of hunting.

Self defense

Semi-automatic rifles are ideal for self-defense. Most semi-automatic rifles are light weight and easy to shoot, without giving up accuracy. Some styles of semi-automatic rifles are more intimidating in appearance to a potential threat, which lowers a person’s chance of actually having to fire their weapon in the event of a home invasion or any other threat that would require some form of self defense. Most semi-automatic rifles also have the ability for their range to be adjusted while keeping the power the same, allowing the owner to keep their weapon at a closer range while in their home, which, in the event the weapon was fired, the bullet would not travel as far, making for a lesser chance of an accident. This keeps their accuracy up and the possibility of shooting outside the intended target lower. Most semi-automatic rifles can be used for all three of these purposes, and are therefore ideal for an all around weapon or gun, due to their versatile nature. The more versatile the weapon is, the more comfortable an owner can become with their weapon, which lessens the probability of accidents[17].

See also


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

  1. Johnson (1944) p.45
  2. Johnson (1944) p.43
  3. Johnson (1944) pp.352-357
  4. Johnson (1944) pp.41,71&79
  5. Jewison, Glenn; Steiner, Jörg C. (2010). "Ferdinand Ritter von Mannlicher". Glenn Jewison.
  6. Smith, Walter H.B. (1947). Mannlicher Rifles and Pistols: Famous Sporting and Military Weapons. Military Service Publishing.
  7. "Firsts: Springfield 375". 2011. Archived from the original on March 14, 2012.
  8. Hogg, Ian (2002). Jane's Guns Recognition Guide. Jane's Information Group. ISBN 0-00-712760-X.
  9. BBC News. "America's Gun Culture in Charts". BBC News. BBC. Retrieved 29 October 2019.
  10. Oxford Dictionary. "Assault Rifle". Oxford Dictionary. Oxford Dictionary. Retrieved 30 October 2019.
  11. Ellis, Will. "5 Best Overall Semi-Automatic Rifles". Gun News Daily. Gun News Daily. Retrieved 29 October 2019.
  12. Miller, Andrea. "What to Know About Machine Guns". ABC News. ABC News. Retrieved 29 October 2019.
  13. Nichols, Chris. "How is a Mass Shooting Defined". PolitiFact. PolitiFact inc. Retrieved 29 October 2019.
  14. Swisher, Skyler. "the AR-15: Killing Machine or America's Gun". Sun Sentinel. Sun Sentinel Inc. Retrieved 29 October 2019.
  15. Encyclopedia Britannica. "Shooting". Encyclopedia Britannica. Encyclopedia Britannica. Retrieved 29 October 2019.
  16. Brenton, Bartt. "5 Reasons to Hunt with an AR-15". Brenton Performance Grade Hunting Rifles. Bartt Brenton. Retrieved 29 October 2019.
  17. McGough, Steven. "Why semi-Automatic Rifles are a Good Choice for Home Defense". RadioVice Online. RadioVice Online. Retrieved 29 October 2019.
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