Semi-automatic rifles and carbines are some of the most popular and widely produced firearms in the United States. Useful for self-defense, hunting, competitive target shooting, private security, and law enforcement, these weapons have become a staple of American life.
Semi-Automatic Operation
Semi-automatic rifles have existed for more than a century, originating in the latter half of the 19th century. In 1884, Hiram Maxim introduced his famous Maxim gun, the first fully automatic machine gun that used the fired cartridge’s power to perform the reloading cycle. Firearms designers took note of this technology and attempted to build handheld weapons — i.e., small arms — that could repeatedly fire.
When you fire a round, the burning propellant produces expanding gases that exert pressure directly against the breech face through the cartridge case head. In blowback- and recoil-operated firearms, this is used as the primary driving force. In gas-operated weapons, the guns use the expanding gases to drive a piston or operating rod or are fed directly into the bolt carrier group.
Fully and semi-automatic rifles perform a series of functions called the cycle of operation every time you squeeze the trigger. These consist of the following:
- Feeding: This is when the bolt, under spring pressure or hand power, strips a round from the magazine and feeds it into the firing chamber.
- Chambering: The cartridge is fully seated in the chamber, reaching its maximum depth.
- Locking: Locking is defined as when the bolt lugs engage corresponding recesses in the barrel extension or receiver, locking the breech. In blowback-operated firearms, the bolt keeps the breech closed using its mass and the driving/recoil spring tension. The purpose of locking is to ensure that the breech remains securely sealed at the instant of firing to contain the high-pressure expanding gases, which is also critical to maintaining gas pressure in the barrel.
- Firing: Squeezing the trigger to release the hammer, which drives the firing pin forward, or the striker, which substitutes for both. Regardless of the particular mechanism, the primer is struck, firing the cartridge.
- Unlocking: Disengaging locking lugs from corresponding recesses in the barrel extension or receiver, or simply opening the breech in blowback-operated firearms, to allow for unloading.
- Extracting: Removing the spent cartridge from the chamber using a part called an extractor that clips over the rim when the round is chambered.
- Ejecting: Removing the spent cartridge from the weapon using a part called an ejector. This part can take many forms, such as a spring-loaded plunger, a pivoting arm, or a fixed lug.
- Cocking: Readying the hammer or striker for the subsequent shot.
What is a Semi-Automatic Rifle?
A rifle is a shoulder weapon with a rifled barrel. Rifles, historically, fit into multiple categories, according to the principle of operation. Bolt- and lever-action rifles, for example, are manually operated. In a semi-automatic rifles, every time you squeeze the trigger, the weapon fires one shot. When you relieve pressure from the trigger, it will reset, allowing you to squeeze it again to fire a subsequent shot. This is how this method of operation works in practice.
All self-loading rifles, whether for sport, combat, or defense, possess the following features:
- Magazine: Most semi-automatic rifles feed rounds from detachable magazines, but there are some notable exceptions. The venerable M1 Garand is fed from en-bloc clips, which holds eight rounds in a staggered column. When the last round is fired, the spent cartridge is ejected along with the clip, producing an audible pinging sound. The SKS, a low-cost, Cold War-era rifle, uses a fixed magazine fed from 10-round stripper clips.
- Stock: Historically, a bolt- or lever-action rifle would have a one- or two-piece wooden stock. The part you would hold in your firing hand would be called the wrist or small of the stock, or the pistol grip, depending on the configuration. Modern defensive or military rifles, such as the AR-15, feature a fore-end or handguard that you grasp with your support hand. The pistol grip is a separate part from the shoulder stock. For increased maneuverability and ease of transport, many semi-automatic rifles have a buttstock that folds or collapses, allowing you to adjust it to suit your comfort.
- Charging handle: Also called a cocking handle, this is the part that you retract to cock and load, or charge, the weapon. This also lets you open the breech to visually inspect the firing chamber and unload the gun for storage or transport.
Common Rifle Calibers
When choosing a semi-automatic rifle for sporting or defensive purposes, it’s crucial to determine what kind of caliber you need. Do you need long-range precision, a light-recoiling defensive round, or smashing power? Whether you’re seeking a rifle for hunting, shooting targets, or protecting yourself, it’s worth considering some of the most well-known.
- .30 Carbine (7.62×33mm): This round is on the list mostly for historical perspective. Before the commercial introduction of the AR-15, the M1 carbine was one of the most common defensive rifles in the U.S. Lightweight, compact, and reliable. The M1 had the advantage of being fed from 15- and 30-round magazines. During World War II, the U.S. War Department contracted companies as diverse as Winchester and General Motors to produce this weapon in the millions. A rimless, straight-walled cartridge, the .30 Carbine resembles a pistol round.
- .223 Remington/5.56mm NATO: The original and still most-popular chambering of the AR-15 rifle, the .223 Remington and its military equivalent, the 5.56×45mm NATO, is light-recoiling, flat-shooting, and has good stopping power.
- 7.62×39mm Soviet: This is the standard cartridge for the AK-47/AKM-pattern and SKS rifles. Designed in 1943, this round has a significant taper to improve feeding and extraction reliability. Loaded with heavier bullets than the 5.56mm cartridge, this round is notably slower.
- .300 AAC Blackout (7.62×35mm): U.S. gun owners have increasingly begun to incorporate sound suppressors into their shooting habits. This round is specifically optimized for use with sound suppressors, available in both subsonic and supersonic varieties. Its supersonic form exceeds the ballistic performance of 7.62×39mm, while only requiring a change of barrel. The bolt face and magazine remain the same.
- .50 Beowulf (12.7×42mm): This cartridge consists of a rebated-rim case loaded with a .50-caliber bullet that’s compatible with both .223-caliber AR-15 breech bolts and USGI 5.56mm magazines. As a result, the .50 Beowulf delivers increased stopping power and penetration for both tactical and hunting uses.
What is an Assault Weapon?
Typically, these weapons are either derived from, or bear a resemblance to, military firearms — i.e., assault rifles, submachine guns, and other weapons carried by soldiers. However, unlike their fully automatic or selective-fire counterparts, assault weapons are always semi-automatic only.
On September 13, 1994, the U.S. Congress passed the Violent Crime Control and Law Enforcement Act, which President Bill Clinton signed into law. Included in this law was the Public Safety and Recreational Firearms Use Protection Act, more commonly known as the Federal Assault Weapons Ban.
This federal law prohibited the manufacture, sale, transfer, and possession of certain types of firearms for a period of 10 years, expiring in 2004. However, the law did not apply to weapons manufactured before the date of enactment; therefore, millions of weapons were grandfathered.
The defining characteristics of an assault weapon are not concrete. However, there are several prohibited features that restrictive legislation includes, such as:
- High-capacity magazines: Legislators often attempt to restrict the number of rounds a detachable box magazine can legally hold to 10 or fewer. The law deems magazines capable of holding more than this sum high capacity. Some magazine types, such as drums, are explicitly prohibited. As magazines for AR-15-pattern rifles and carbines typically hold 20 and 30, these can be considered the standard capacity for this weapon platform. It’s also worth noting that a 30-round AR-15 magazine can only hold ten rounds of .50 Beowulf, another popular sporting cartridge; therefore, capacity also depends on the caliber.
- Muzzle device (or threaded muzzle): This can be a muzzle brake, flash suppressor, or sound suppressor, although the legislator’s focus is on the latter two. The purpose of a flash suppressor, also known as a flash hider, is to reduce the muzzle flash’s luminosity to avoid blinding you when you fire your rifle in low-light conditions — at dusk, dawn, or after dark. It doesn’t eliminate the visual firing signature, and, contrary to popular belief, your position will still be revealed at night. As for sound suppressors, these reduce noise pollution and the risk of permanent hearing loss. Before their addition to the National Firearms Act, sound suppressors, also known as silencers, were routinely used by recreational shooters and hunters.
- Bayonet lug: A metal part near the muzzle that allows you to attach a bayonet — a type of knife — which soldiers use as a rifle-mounted thrusting weapon.
- Collapsible/folding buttstock: Often portrayed as allowing you to conceal a rifle under a trenchcoat, the primary purpose of a collapsible (or telescoping) stock is to enable length-of-pull adjustment — the distance between the face of the trigger and the butt — to accommodate shooters of different heights. A folding stock does reduce the overall length of the weapon for storage and transport.
- Barrel shroud: Defined sometimes as a heat shield that encircles the barrel, the argument is that this feature allows you to fire continuously without interruption, which increases the lethality of the weapon. A heat shield is a safety device. It protects you from burning your hand on a hot barrel.
What is an Assault Rifle?
Assault rifle, assault weapon, and military-style semi-automatic rifle are often used interchangeably. However, historically, this is not correct. Assault rifle is derived from sturmgewehr — German for storm rifle — and refers to a specific type of firearm.
For a firearm to be defined as an assault rifle, it must be capable of fully automatic or burst fire. These firing modes are usually selectable using a lever on the receiver’s side. Weapons of this type are regulated under the National Firearms Act of 1934 and the Gun Control Act of 1968 as machine guns. While legal, civilian ownership of machine guns is restrictive.
In 1986, the Firearm Owners’ Protection Act prohibited the continued manufacture of machine guns for private sale. As a result, for a machine gun to be transferable — legal for an unlicensed private citizen to buy — the weapon must have been manufactured and registered with the BATF before May 19, 1986. This compulsory supply cap has rendered legally owned fully automatic weapons scarce and expensive.
Assault Rifle Power
Another characteristic that defines an assault rifle is that it must fire an intermediate-powered cartridge, which would correspond to .223/5.56mm and 7.62×39mm, among others. Many gun-control advocates assert that an assault rifle is capable of inflicting fatal injuries or severe wounds. However, standard hunting rifle and shotgun cartridges — .243, .270, 30-30, .30-06, and 12 and 20 gauge — are more powerful and inflict more traumatic wounds.
The AR-15 Rifle
Called America’s rifle and the black rifle affectionately by gun owners, the AR-15 rifle is both glorified and demonized in the United States. It is, nonetheless, our national rifle. Before discussing this American classic’s finer points, it’s essential to clarify a point regarding terminology. AR-15 does not, as some may believe, stand for assault rifle. Instead, it refers to ArmaLite Rifle Model 15 — an allusion to the company whose team, led by Eugene Stoner, designed it.
The AR-15 is a semi-automatic, gas-operated rifle fed from a detachable box magazine. Initially chambered in .223 Remington, the rifle pattern is highly versatile and can accommodate a wide variety of cartridges, owing to its increasing popularity.
That’s what the rifle platform is known for — nearly endless customizability. This type of platform allows you to personalize your rifle to suit your aesthetic tastes, preferred application, and more. These range from different handguards — M-LOK, KeyMod, quad rail, etc. — pistol grips, buttstocks, fire-control groups, and sights to bolt-carrier groups.
Weapons conforming to the AR-15 pattern are called defensive rifles and tactical rifles, reflecting their use as home-defense and law-enforcement weapons.
Rifles for Home Defense
Many private citizens choose to own and carry handguns for self-defense. The pistol provides what many regard as the optimal balance of portability and firepower. However, while the handgun is the best choice for concealed and open carry, owing to its convenience, the long gun is arguably the superior choice of weapon for home defense.
Historically, one of the classic home-defense weapons in the United States has been the 12- or 20-gauge shotgun. This is an understandable extension of the shotgun’s place as duty or patrol long gun — police officers would often keep a 12-gauge riot gun in their squad car. Police weaponry patterns have shifted in recent years to the rifle, and there has been a corresponding increase in private citizens’ use of such weapons.
A rifle, especially a defensive carbine, in .223 caliber (5.56mm), produces considerably less recoil than a 12- or 20-gauge repeating shotgun firing buckshot or slug rounds. Unlike a handgun, rifle ammunition, including of the intermediate variety, delivers increased wounding power.
The defensive rifle also has the advantages that you’d expect from a shoulder weapon — multiple points of contact and a longer sight radius for improved sight picture acuity.
The additional points of contact — your strong hand on the pistol grip or wrist of the stock, support hand on the fore-end, butt nestled in the pocket of your shoulder, and cheek against the comb — increases the stability of this weapon platform. This enables you to more effectively control the weapon under a variety of conditions.
When taken together, all these demonstrate that the rifle is a highly useful weapon for home defense. Some may raise the question of penetration. Isn’t a rifle cartridge too penetrative for use inside a residential house? It’s worth noting that many handgun loads, including those consisting of jacketed hollow-point bullets, will penetrate multiple interior walls.
However, expanding or frangible bullets in .223 Remington and 5.56mm NATO can fragment upon striking drywall and plywood, rendering them less dangerous to bystanders located inside the home. You must always determine what you consider to be an appropriate caliber and load to suit your individual circumstances.
Ranch or Retreat Defense
Whether you’re a farmer, a rancher, or a survivalist, the semi-automatic rifle also has uses outside of a traditional suburban environment. In desolate areas, where access to emergency services is exceptionally scarce, the semi-automatic rifle offers increased rapidity and fire continuity compared with manually operated sporters.
Semi-Automatic Rifles in Hunting
The first semi-automatic hunting rifle to see widespread commercial use hit the market more than a century ago. This type of action allows for rapid follow-up shots with less disturbance of your sight picture, as you don’t have to manipulate the bolt manually. This can be essential when hunting dangerous game and affords the hunter the ability to more reliably take fast-moving game animals, varmints, and predators afield more.
Some gun owners also find that the semi-automatic action itself, which in rifles almost always uses a gas piston or operating rod, is softer shooting than manual-action repeaters. One explanation for this is that when you fire a bolt-action rifle, the rifle recoils as a single unit. In contrast, when you fire a semi-automatic rifle, the barrel, receiver, and stock — the fixed mass — remains stationary. It’s only the reciprocating action that you feel the recoil of, so it’s also able to compress a recoil or return spring to decelerate.
Another reason is that when the gas applies pressure against the piston or operating rod to send the action rearward, it’s applying equal pressure against the gas cylinder’s front, which forces the gun forward.
The Bottom Line
At IFA Tactical, we believe in the Second Amendment and that this right extends to semi-automatic rifles for lawful purposes, such as self-defense and hunting. If you’d like to discuss the differences between semi-automatic and selective-fire weapons with us or would like advice on what rifles or accessories to buy, give us a call at (586) 275-2176.
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Additional resources
What Do Semi-Automatic Rifles Mean For Hunting?
The Most Versatile Semi-Automatic Rifles: 2020 Buying Guide & Reviews
