Question

when a rifle fires, a sequence of events takes place. after the firing pin strikes the primer, what is the next event in the sequence?
a expanding gas drives the bullet through the barrel.
b gunpowder burns and converts to a gas.
c the trigger is pulled.
d the primer explodes and ignites the gunpowder.

Explanation:

When the firing pin strikes the primer, the primer explodes first. This explosion then ignites the gunpowder. After the gunpowder burns and converts to gas, the expanding gas drives the bullet through the barrel. The trigger being pulled is the event that causes the firing pin to strike the primer, so it is not the next event after the firing pin strikes the primer.

Answer:

D. The primer explodes and ignites the gunpowder.