What is the propellant used in most firearms that produces a large volume of gas when ignited?

• A. Powder
• B. Primer
• C. Rim
• D. Headstamp

Answer: (A)

Firearm propellants are powders that burn rapidly to produce high-pressure gas, which pushes the bullet down the barrel. In most cartridges, that propellant is called powder—modern smokeless powder specifically is a form of powder designed to generate a large volume of gas as it burns. This rapid gas production is what creates the pressure needed to move the bullet out of the firearm.

The other terms refer to different cartridge parts: the primer is the ignition source that lights the powder; the rim describes the edge on rimmed cartridge cases; the headstamp is the identifying mark on the base of the cartridge case. So the propellant described here is powder.