- The following events all take place during the firing of a firearm. Put them in order from the 1st event to the 9th event. __ Casing is ejected from firearm __ Primer powder sparks through the flash hole to the gunpowder __ Bullet is expelled from casing into the barrel __ Pressure of exploding propellant exerts force on bullet inside casing __ Gunpowder explodes __ Firing pin is released and hits base of cartridge __ Cartridge enters chamber while firing pin is cocked back __ Bullet follows lands and grooves (if present) and ejects from the barrel __ Trigger is pulled