Types of Firearms

1911 Pistol

Why 1911? The “1911” was given its name because the pistol was adopted by the U.S. Army in the year 1911.

The M1911 is also known as the Colt 1911 or the Colt Government. John Browning designed the pistol in the late 1890s to replace the variety of revolvers then in service with a self-loading (or semi-automatic) pistol. The 1911 is a single-action, semi-automatic, magazine-fed, recoil-operated pistol chambered for the .45 ACP cartridge. This operating system became the most popular of nearly all the modern centerfire pistols adopted during the 20th century. The gun served as the standard-issue sidearm for the U.S. Armed Forces from 1911 to 1985. Modern variants of the pistol are still used by the U.S. Army Special Forces, the U.S. Marine Corps and the U.S. Navy today.

AR-15

The “AR” in AR-15 stands for ArmaLite Rifle — not for “assault rifle” or “automatic rifle” as commonly misconstrued. During the 1950s, ArmaLite developed the AR-15 as a military rifle. By 1959, the company sold the patent and manufacturing rights to Colt. Colt released the first civilian model — the AR-15 Sporter, a semi-automatic version chambered for .223 Remington — in 1964. Colt’s patents for the AR-15 expired in the 1970s, prompting other manufacturers to begin producing similar models based on its design.

AR-15 style rifles have become so popular predominantly because of their versatility. They come in many sizes and with a multitude of options, depending on the manufacturer. The majority of AR-15s are chambered for the 5.56 NATO. However, they may be chambered in nearly any caliber — ranging from .22 long rifle to the massive .50 Beowulf.

AR Pistol

An AR-15 pistol is a pistol-length AR-15 with no stock (only rifles have stocks). In place of a stock, an AR-15 pistol usually has a pistol buffer tube or similar piece that does not allow for the attachment of a traditional stock. To qualify as a pistol, there must be no vertical foregrip. An AR-15 pistol has a barrel shorter than 16 inches — this is the minimum legal length for a rifle barrel.

The National Firearms Act of 1934 (NFA) defines any rifle with a shoulder stock and barrel less than 16 inches in length and 26 inches in overall length to be a “short-barreled rifle” (SBR). It requires a citizen to fill out ATF Form 4 and pay a $200 NFA Tax Stamp. An AR-15 pistol allows the shooter to have the size, weight and maneuverability of an SBR but avoids the NFA regulations. An AR pistol is fired like a typical handgun. The barrel size is usually 7 inches or 10.5 inches, giving the shooter greater flexibility in close-quarters shooting. It is a great home-defense firearm for this reason. Due to its size, an AR pistol is easy to store and transport.

Autoloading Firearms Operating Systems

Blowback-Operated Systems

Semi-automatic firearms use many different mechanisms for cycling the action (the mechanism that moves ammunition through a firearm). Blowback-operated firearms are among the least complex. Other operating principles for self-loading firearms include blow-forward, gas-operation and recoil-operation.

Blowback is a system of operation for a self-loading firearm that obtains energy from the motion of the cartridge case as it is pushed to the rear by expanding gas created by the ignition of the propellant charge. A blowback firearm features an unlocked breech. The breech is the rear of the barrel that opens into the chamber. When the slide (the part that reciprocates to feed ammunition through a firearm) moves into its most forward position, it’s referred to as being “in battery.” An unlocked breech slide does not lock to the barrel when fired.

A blowback firearm uses force created by burning gunpowder to cycle the action. The gas from a blowback-operated pistol pushes the bullet down the barrel when fired. As the bullet moves forward, the slide blows back under the pressure of the fired round. After the pressure drops to a safe level, the breech moves backward, extracting and ejecting the case. Once the case ejects, the slide moves forward, stripping another round off the top of the magazine, back into battery. The cycle is then ready to start again.

A blowback-operated firearm typically lacks a mechanical lock between the breech and the barrel. This makes it simpler to design and cheaper to build. A gas- or recoil-operated firearm requires a more complex system to lock and unlock the bolt. A blowback-operated firearm is quite reliable. This is because of the forcefulness of its ammunition being fed (extraction keeps it working consistently).

Several blowback systems exist within this broad principle of operation. Each is distinguished by the methods used to control breech movement. A few locked-breech designs use a form of blowback — such as the primer actuation — to perform the unlocking function. Delayed blowback or retarded blowback is a subclass of blowback operation.

Recoil-Operated Systems

A recoil-operated firearm uses the energy of recoil to cycle the action. It is one of the earliest and most successful methods of operation for an automatic firearm. It works for a broad spectrum of weapons — from pocket-sized pistols up to heavy machine guns and automatic cannons.

Hiram Maxim, an American inventor living in Europe, was probably the first person to utilize the energy of recoil to automatically cycle the action of a gun, receiving a patent in 1884. The successful design quickly gained acceptance with firearm designers in many countries, including Hugo Borchardt (1893), the Federle brothers (1894) and John Browning (1896).

Gas-Operated Systems

A gas-operated firearm is one that uses the energy from a portion of high-pressure gas from the cartridge being fired to work the action in semi-automatic and fully automatic guns. One of the earliest gas-operated designs belongs to the French Clair brothers (Jean Baptiste, Benoit and Victor), who patented a gas-operated rifle in the 1890s.

Direct-Impingement

The major difference between a direct-impingement firearm and a gas-piston-operated firearm is where the gas goes after helping to expel from the barrel. In a direct-impingement gas system, the gas created from firing gets pushed along the barrel with the bullet until it hits the gas block. The bullet will then leave the barrel, but the gas is forced up into the gas tube and directed back along the length of the barrel and into the gas key. At this point, the gas forces the bolt carrier group back to eject the spent case and load the next round.

Piston-Operated

A gas piston cycles the action in the same manner. But the notable difference is that the gas never cycles back to the carrier group. Instead, when a shot is fired, the gas forces the bullet down the barrel and reaches the gas block. Rather than traveling along the gas tube and back into the chamber, the gas stops just above the gas block, hits a solid piston and expels out at that point. The gas still goes up and out of the barrel with the same amount of force. Therefore, it still has the power to cycle the bolt carrier group just as effectively.

Curio and Relic (C&R)

A regulation implementing federal firearms laws, 27 CFR §478.11, defines curio and relic (C&R) firearms as those which are of special interest to collectors by reason of some quality other than association with firearms intended for sporting use or as offensive or defensive weapons. They may have been manufactured at least 50 years prior to the current date, certified by the curator of a museum, are novel, rare or bizarre, or are associated with some historical figure, period or event.

Double-Action (DA)

The double-action (DA) revolver uses a long pull of the trigger to cock the hammer, rotate the cylinder and fire the piece. Repeated shots may be fired by repeatedly pulling the trigger until all rounds have been fired. Many DA revolvers may be thumb-cocked and fired in single-action mode as well, while others have enclosed hammers and may be fired only in double-action mode.

Double-action firearms have a longer, stiffer trigger pull than a single-action gun because you’re doing the extra work of cocking the hammer with the trigger.

Single-Action (SA)

A single-action (SA) trigger is the earliest and mechanically simplest of trigger types. Single-action means pulling the trigger does one action: It releases the hammer or the striker. With a single-action pistol, if the gun’s not cocked, pulling the trigger actually does nothing. You have to manually pull the hammer back, and then pulling the trigger will release it. Cocking the hammer rotates the cylinder. This action brings a new round into alignment with the barrel. Once cocked, the SA revolver trigger must be pressed to fire. The hammer must be re-cocked to fire another round. A single-action pistol will have a shorter, lighter trigger pull than a double-action because the hard part — pulling back the hammer — is already done.

The term SA was not used until the introduction of double-action revolvers in the mid-19th century. Prior to that, all triggers were SA (matchlocks, flintlocks, percussion rifles, etc.)

Double-Action/Single-Action (DA/SA)

A double-action/single-action (DA/SA) firearm combines the features of both double- and single-action mechanisms. When the firearm discharges, the cycling slide will automatically cock the hammer to the rear. The rest of the shots fired will be in single-action mode, unless the hammer is manually lowered again. This action is also known as traditional double-action (TDA).

DA/SA typically refers to a semi-automatic, but in the case of a revolver, double-action generally means a weapon combining the ability to fire both double- and single-action. The trigger mechanism function of a DA/SA semi-automatic handgun is identical to a DA revolver. However, this is combined with the ability of most semi-automatics to self-cock the hammer when firing. The pistol can be carried with the hammer down on a loaded chamber, unlike a single-action semi-automatic. When the user is ready to fire, simply pulling the trigger, in double-action mode, will cock and release the hammer. This gives the positive aspects of a single-action trigger without the need to carry “cocked and locked” (with a loaded chamber and cocked hammer), or with an empty chamber, which requires the user to chamber a round before firing.

Double-Action (DA) or Double-Action Only (DAO)

A double-action, also known as double-action only (DAO), is a design which either has no internal mechanism capable of holding the hammer or striker in the cocked position (semi-automatics), or has the entire hammer shrouded and/or has the thumb spur machined off, preventing the user from cocking it (revolvers).

This design requires a trigger pull to both cock and trip the hammer/striker for every single shot, unlike a DA/SA, which only requires a double-action trigger pull for the first shot (or a typical DA/SA revolver, which can fire single-action, but uses double-action as a default). There is no single-action function for any shot. The hammer or striker always rests in the down position until the trigger pull begins. With semi-automatics (unlike DA/SA weapons) the hammer does not remain cocked after the first round is fired. Every shot is in double-action mode. When it comes to a revolver, the shooter does not have the option of cocking the gun before shooting and must always discharge it in double-action mode.

Hammer Fired

The primer must be dented in order for a gun to fire. With a hammer-fired gun, a spring-powered weight (hammer) swings into the firing pin when released by the trigger. That impact on the back of the firing pin drives the pin into the cartridge’s primer. In some cases, the firing pin is integral to or attached to the hammer itself. Hammers are more commonly seen on the outside of a handgun, but there are many designs with internal hammers.

Striker Fired

The primer must be dented in order for a gun to fire. The hammer and mainspring have been eliminated from the frame of a striker-fired gun. Instead, the mainspring is positioned within the slide and acts on the firing pin directly. In this instance, the firing pin is called a striker. Rather than being hit by a hammer, it does the hitting itself.

Some striker-fired guns are single-action (SA), where the cycling of the slide fully cocks the striker and the trigger serves only to release it. Others are double-action (DA), where the trigger pull fully cocks or finishes cocking the striker, then releases it. Some are DA/SA and may even have an external decocker so a round can be chambered with the hammer down.

Handgun

A handgun is a firearm designed to be fired with one hand, especially a pistol or revolver.

J-Frame Revolvers

The Smith & Wesson (S&W) J-frame is the smallest class of its revolvers. S&W had two frame sizes in 1894 when it designed the side swing or swing-out-cylinders line of revolvers. The smaller-sized frame was called the “I-frame,” and the larger-sized frame was known as the “K-frame.” These designations were an internal way for employees to identify the frame sizes. However, S&W employees began using the internal frame designations in discussions with journalists, leading to their widespread use.

The J-frame was introduced in 1950. Ten years later, the smaller I-frame revolvers chambered for the less-powerful .38 S&W cartridge were discontinued. All small-frame guns made since have been built on the J-frame.

Did You Know?

A 200-Year-Old Legacy of Entrepreneurship

The Wesson family can trace their history of entrepreneurship back 200 years. Massachusetts native Rufus Wesson (1786-1873) was an expert producer of wooden plows. His sons Edwin (1811-1849) and Daniel (1825-1906) became gunsmiths. In 1852, Daniel Wesson partnered with Horace Smith to establish the Smith & Wesson Company. The younger Wesson brother Franklin (1828-1899) also pursued a career as a firearms manufacturer, partnering with his nephew to found Wesson & Harrington (later the Harrington & Richardson Company).

Smith & Wesson Factory, Springfield, Massachusetts, circa. 1908 (Image courtesy of the Library of Congress)

K-Frame Revolvers

The S&W K-frame is larger than the J-frame. It is one of S&W’s original models that has a swing-out cylinder. Like the I-frame, it had been around since the 1890s. It is known as the “.38 frame,” as it was designed specifically for that cartridge.

L-Frame Revolvers

The L-frame was designed to be a sturdier K-frame. This was accomplished by adding more steel and greater strength in critical areas to handle the power of the .357 Magnum. It became one of the most popular duty guns of the time.

Pistol

A pistol is generally a handgun that operates semi-automatically and utilizes a detachable box magazine to hold cartridges, usually, but not always, inside the grip.

Pistol-Grip Firearm

A pistol-grip firearm is a firearm that was not manufactured with a buttstock and is not intended to be fired from the shoulder. It fires shotgun shells and is more than 26 inches in overall length. It doesn’t fit the ATF’s definition of a shotgun or a handgun, hence the name.

Revolver

A revolver (also called a wheelgun) is a repeating handgun that has a revolving cylinder containing multiple chambers and at least one barrel for firing. When the trigger is pulled or the hammer is cocked, the cylinder rotates behind the barrel to present a new chamber to be fired.

An automatic weapon is one that loads another round mechanically after the first round has been fired. It can be semi-automatic, firing one shot per single pull of the trigger, or fully automatic, loading and firing ammunition until the trigger is released, the ammunition is exhausted or the weapon malfunctions.

Fully automatic is the mode of operation of a firearm whereupon the trigger is pulled and multiple shots are fired and will continue to fire until the trigger is released or until the magazine is empty. This mode of operation is extremely rare, heavily federally regulated and impossible for private citizens to purchase in a regular gun shop or at a gun show.

Did You Know?

Italy’s First Automatic Rifle

Captain Amerigo Cei-Rigotti of the Italian Army introduced one of the world’s first automatic rifles in 1900. Cei-Rigotti designed the rifle to fire both semi-auto and fully auto. He presented his gas-operated rifle to the Italian War Ministry, which had a regiment test its efficiency. The unit’s soldiers fired 432,000 rounds in two minutes with their traditional weapon, compared to 1,125,000 rounds with Cei-Rigotti’s design. Despite its impressive rate of fire, the Cei-Rigotti rifle was never adopted for regular use by the Italian Army before World War I.

Illustration from Office of Naval Intelligence, Notes of Naval Progress, July, 1901, Washington, D.C.: Government Printing Office, 1901

Semi-Automatic

Semi-automatic is the mode of operation of a pistol, rifle or shotgun whereupon the trigger is pulled and a single shot is fired. Energy from firing is used to reload the chamber and re-cock the firing mechanism for another trigger pull. Can also be termed “self-loading.”

Single Shot

Single shot is the mode of operation where a weapon has no magazine and may contain only a single cartridge, loaded directly into the chamber. The gun must be manually reloaded and manually re-cocked every time it is fired. It is most commonly found in large hunting handguns, simple shotguns or hunting rifles.

Short-Barreled Rifle (SBR)

A short-barreled rifle (SBR) is defined by the National Firearms Act of 1934 (NFA) as a shoulder-fired, rifled firearm, made from a rifle, with a barrel length of less than 16 inches or overall length of less than 26 inches, or a handgun fitted with a buttstock and a barrel shorter than 16 inches in length. An SBR is regulated by the ATF as a Title II weapon. In the absence of local laws prohibiting ownership, a private citizen may own an SBR, provided it is registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). A $200 tax is paid prior to taking possession of or creating the firearm.

Snub-Nosed Revolver

A snub-nosed revolver is any small, medium or large frame revolver with a short barrel, which is generally 3 inches or less in length. They are primarily designed for maneuverability and concealment. These revolvers were extremely popular in the U.S. until the 1950s and 1960s, when most states passed laws limiting or prohibiting the carry of concealed weapons. They are manufactured in a wide variety of calibers.

Did You Know?

The British Bulldog

The British arms manufacturer P. Webley & Son introduced the Bulldog revolver during the 1870s. The five-shot revolver was known for its stubby, compact design — hence the bulldog moniker. The revolver was intended to be used for home defense and easily could be concealed in a coat pocket. An assassin used a .442 Webley Bulldog to gun down President James A. Garfield at the Baltimore and Potomac Railroad Station in Washington, D.C., in July 1881.

Image courtesy of Heritage Auctions, HA.com

Title I Firearms

Title I firearms are ordinary rifles, pistols, revolvers and shotguns. Title I firearms can be owned and built by U.S. citizens who can legally possess firearms.

Title II Firearms/NFA Firearms — Title II of the Gun Control Act of 1968 is an amendment of the National Firearms Act of 1934, pertaining to machine guns, short-barreled or “sawed-off” shotguns and rifles, and so-called “destructive devices” (including grenades, mortars, rocket launchers, large projectiles and other heavy ordnance). The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) refers to such weapons as “NFA firearms.” Acquisition of these weapons is subject to prior approval of the Attorney General. Federal registration is required for possession. This amendment revised the definition of “firearm” by adding “destructive devices” and expanded the definition of “machine gun.” Title II firearms fall into six categories:

• Machine Guns
• Short-barreled rifles (SBRs) having a barrel or barrels of less than 16 inches in length or any weapon made from a rifle if the modified weapon has an overall length of less than 26 inches or a barrel or barrels of less than 16 inches in length
• Short-barreled shotguns (SBSs) having a barrel or barrels of less than 18 inches in length or any weapon made from a shotgun if the modified weapon has an overall length of less than 26 inches, or a barrel or barrels of less than 18 inches in length
• Suppressors
• Any other weapon (AOWs), as defined in subsection (e)
• Destructive devices

Title II firearms can only be sold by Federal Firearm dealers (FFLs) with a Class III license.