Which of the following describes the role of expanding gas after powder burns?

• A. Expanding gas drives the bullet through the barrel
• B. The primer explodes and sparks the gunpowder
• C. The trigger is pulled
• D. Gunpowder burns and converts to a gas

Answer: (A)

When the powder burns, it rapidly creates high-pressure gas inside the cartridge. This expanding gas pushes against the base of the bullet, driving it forward and down the barrel. That propulsion is what moves the bullet toward the target. The primer’s job is to ignite the powder, starting the burn, while the trigger just initiates firing. Saying the gas simply burns the powder or that the trigger causes the gas doesn’t describe the gas’s main role, which is to propel the bullet out of the barrel.