What is the difference between caliber and gauge?

What is the difference between caliber and gauge?

• A. Caliber refers to shotgun bore size; gauge refers to bore diameter for rifles.
• B. Caliber refers to a cartridge’s bore diameter for rifles/pistols; gauge refers to shotgun bore size.
• C. Caliber is the length of the barrel.
• D. Gauge is the weight of the cartridge.

Answer: (B)

Caliber describes the bore diameter for rifles and pistols and is tied to the bullet size that fits the bore. It’s measured in inches or millimeters, so you’ll see things like 9mm or .30 caliber, indicating the diameter of the bullet the gun is designed to fire. Gauge, used for shotguns, is a separate system that defines bore size in a different way: it’s based on how many lead balls of that bore diameter would weigh one pound. That’s why a larger bore has a smaller gauge number (12 gauge is larger than 20 gauge). In short, caliber = rifle/pistol bore diameter (bullet size); gauge = shotgun bore size defined by the lead-ball-in-a-pound concept.

Caliber describes the bore diameter for rifles and pistols and is tied to the bullet size that fits the bore. It’s measured in inches or millimeters, so you’ll see things like 9mm or .30 caliber, indicating the diameter of the bullet the gun is designed to fire. Gauge, used for shotguns, is a separate system that defines bore size in a different way: it’s based on how many lead balls of that bore diameter would weigh one pound. That’s why a larger bore has a smaller gauge number (12 gauge is larger than 20 gauge). In short, caliber = rifle/pistol bore diameter (bullet size); gauge = shotgun bore size defined by the lead-ball-in-a-pound concept.