A firearm is generally a rifle, pistol, shotgun, or other portable weapon that expels a projectile (bullet) by use of an explosive action. The definition of a firearm may vary from state to state under state statutes—and under federal statutes—and related items such as a muffler or silencer may be included in the definition of a firearm for purposes of certain criminal offenses (crimes).

In Louisiana (LA), a firearm is defined under state law as any pistol, rifle, shotgun, or other instrumentality used to expel a projectile through the action of an explosive. The definition is consistent with the general understanding of what constitutes a firearm, and it includes any weapon that can be used to fire a bullet or projectile. Additionally, accessories such as mufflers or silencers can also be considered part of a firearm for the purposes of certain criminal offenses. This means that possession or use of a silencer, for example, may be subject to the same regulations and penalties as the firearm itself. It's important to note that federal law also has its own definitions and regulations regarding firearms, which include the National Firearms Act and the Gun Control Act, and these federal laws apply in Louisiana as well as all other states. Under federal law, the definition of a firearm also includes certain other components and accessories, such as silencers and destructive devices. Individuals in Louisiana must comply with both state and federal regulations concerning firearms.