He had four weapons, including an assault rifle, on him after the rampage that killed 12 people and injured 58 at a midnight movie screening.
His American-style rifle jammed on an oversized round magazine.
He should have just brought two semi sawed off shotguns and used buckshot sized pellets. In a theatre (not military theatre, ha!) this is more useful. (And in a military theatre where you're fighting in tunnels, a shotgun is traditionally preferred by (losing) american invaders.)
Not even a nice ole reliable AK. Just shotguns. Keanu style.
Not sure how you reload a shotgun quickly though, I don't own one. Should though. Do any take magazines? Doubt it ----Business opportunity! The StreetSweeper had a rotary holder/feeder for its 12g rounds, but I'm not sure how fast it was to reload.
When the zombie (etc...) apocalypse happens, I should probably have practiced with a shotgun, which I've never even held.
OTOH I have a rifle that will destroy an engine...