Firearms 101
What is a firearm?
The term “firearm” as defined by 27 CFR 53.11 is “Any portable weapon, such as rifles, carbines, machine guns, shotguns, or fowling pieces from which a shot, bullet or projectile may be discharged by an explosive.”
“Firearm” officially applies to gunpowder-based devices, but is widely used to describe any device that propels a projectile (regardless of propellant). We will loosely use the term “firearm”, but we focus on those devices that fit the official definition.
What are the different types of firearms?
Firearms can be categorized in different ways, based on features and design. Note that these categories are not mutually exclusive and that the same firearm can be classified in multiple ways. For example, you can have a single shot (Action Type) black powder (Propulsion) rifle (Design) that fires a large caliber projectile (Caliber or Bore).
Firearm Propulsion
Gunpowder (combustion) as a propellant:
- Black Powder, also known as gunpowder, is an explosive mixture of sulfur, charcoal, and potassium nitrate (saltpeter). When ignited, black powder burns rapidly, producing large amounts of smoke and gas. This creates a visible cloud of smoke and a loud report. Black powder is a low-velocity propellant and is mainly used in antique firearms and in some modern muzzleloading firearms. Typically, black powder firearms are loaded from the muzzle of the barrel. The powder charge is loaded first and is followed by the projectile(s). These firearms then use a percussion cap or a flintlock to ignite the powder, and this produces a small flame that travels through a touch-hole, which travels to the main powder charge and ignites the powder. While black powder firearms are a nostalgic and challenging tool for recreation and hunting, we will not cover this category of firearm any further. If you are interested in learning more about black powder firearms, Free Range American has a great historical review.
- Smokeless powder is a modern propellant that is more powerful and efficient than black powder. It is composed of nitrocellulose and other chemicals, and it burns more cleanly and efficiently than black powder. When ignited, smokeless powder burns much faster and hotter than black powder, producing a high-pressure gas that propels the bullet at higher velocities. This creates less smoke and a much louder report than black powder.
- Rimfire Cartridge Rimfire ammunition has an explosive primer compound located in the rim of the cartridge base. When the firing pin strikes the rim, it crushes the rim, causing the primer compound to detonate, which in turn ignites the gunpowder and propels the bullet out of the case and down the barrel. Rimfire cartridges are typically used in small caliber firearms, such as .22 rifles and handguns.
- Centerfire Cartridge Centerfire ammunition has an explosive primer located in a small cup in the center of the cartridge base. The firing pin strikes the primer cup, causing the primer compound to detonate, which ignites the gunpowder and propels the bullet. Centerfire cartridges are used in a wide range of firearms, from pistols to rifles and shotguns. This is the category that is regulated by the federal government and most relevant to the average Joe. As such, the majority of content on this site and services provided by Para Bellum focus on this category.
Compressed gas (pneumatic) as a propellant:
- Airguns are guns that use compressed air or gas as a propellant. They are typically used in target shooting, pest control, and hunting small game. Air rifles and pistols are excellent, low-cost ways to train. They can be substituted in place of gun powder-based firearms for a more discrete, safer, and less expensive way to put “rounds” down range. Whether practicing drawing from a holster, refining shooting technique, or having some fun in the backyard, these are fantastic additions to any firearms collection.
Electromagnetic force (railgun or coilgun) as a propellant:
- Railguns are weapons that use parallel conductors (rails) and a sliding armature to accelerate a projectile at extremely high velocities. They are primarily used in military applications.
- Coilguns are weapons that use a series of electromagnetic coils around a bore to propel a projectile. They are typically used for research purposes and are not yet widely available for civilian use.
EM weapons are generally only effective (in cost and function) in a military application (or research supporting military-scale use). Some hobbyists tinker with this technology, but the results do not warrant civilian attention, at this time. As such, we will not cover this class of weapons any further.
Firearm Action
- Single-shot firearms: firearms that require manual reloading after each shot.
- Lever-action firearms: firearms that use a lever near the trigger guard that is manually operated by the shooter to cycle the action and reload the chamber from a magazine.
- Bolt-action firearms: firearms that use a bolt that is manually operated by the shooter to cycle the action to reload the chamber from a magazine.
- Semi-automatic firearms: firearms that automatically reload the chamber from a magazine after each shot but require the trigger to be pulled for each shot.
- Fully automatic firearms: firearms that can fire multiple rounds continuously with a single trigger pull.
Firearm Design and Purpose
- Handguns: firearms designed to be fired with one hand, including pistols and revolvers.
- Rifles: long guns that are designed to fire from a shouldered position for accuracy and long-range shooting.
- Shotguns: firearms that use shells loaded with multiple pellets or a single slug.
Firearm Caliber and Bore
- Small caliber firearms: firearms that fire small-caliber bullets, such as .22 LR or 17 HMR. These rounds are often used for target shooting, plinking, and small game hunting.
- Medium caliber firearms: firearms that fire medium-caliber bullets, such as .223 Remington, .308 Winchester, 9mm Luger, or .45 ACP. These rounds are often used for self-defense, law enforcement, and military applications.
- Large caliber firearms: firearms that fire large-caliber bullets, such as .50 BMG and 12-gauge shotgun shells. These rounds are often used for long-range shooting, big game hunting, and anti-material applications.
How Are Firearms Regulated?
Constitutional Right
The Second Amendment generally provisions the right for all citizens to legally own and possess firearms. So, we’ll start there and whittle it down.
Age Restriction
Following the ratification of the Bill of Rights in 1791, the Federal government has applied an age restriction to the applicability of this statement (commentary: while the exact appropriate age may be contested, the principle that a child shouldn’t be able to purchase a firearm is generally well-accepted):
- One must be at least 18 years old to purchase a long gun (rifle or shotgun)
- One must be at least 21 years old to purchase a pistol/handgun.
Federally-Prohibited Persons
The Federal government has also identified certain classes of individuals that are prohibited from possessing (and therefore, purchasing) a firearm. Regardless of the rationale, exceptions, or specifics of these prohibitions, they generally include:
- Convicted felons: Individuals who have been convicted of a felony offense (a crime punishable by imprisonment for more than one year) are generally prohibited from possessing firearms under Federal law.
- Domestic abusers: Individuals who have been convicted of a misdemeanor crime of domestic violence or who are subject to certain domestic violence restraining orders are prohibited from possessing firearms under Federal law.
- Fugitives from justice: Individuals who have fled from a state to avoid prosecution for a felony or to avoid giving testimony in a criminal trial are prohibited from possessing firearms under Federal law.
- Illegal drug users and addicts: Individuals who are illegally using or addicted to a controlled substance (as defined under Federal law) are prohibited from possessing firearms.
- Individuals adjudicated as mentally defective or committed to a mental institution: Individuals who have been adjudicated as mentally defective or who have been committed to a mental institution are generally prohibited from possessing firearms under Federal law.
- Non-U.S. citizens: Non-U.S. citizens who are in the United States on a nonimmigrant visa (with some exceptions) are generally prohibited from possessing firearms.
- Individuals dishonorably discharged from the military: Individuals who have been dishonorably discharged from the U.S. Armed Forces are generally prohibited from possessing firearms under Federal law.
State Restrictions
Additional exceptions may exist at the state or local level. Always consult your local FFL dealer or local law enforcement if you have any questions. If you don’t like the restrictions applied at the state or local level, move.