It is hilarious when in almost every room of the house they are going through they have to rack their pistol or shotgun... they must be leaving unfired cartridges everywhere they go."Re-racked" - I see it a lot on TV, you know, when the character racks the slide several times before employing the weapon.
The action that makes you think either "why is he waiting until now to chamber a round," or "didn't he just eject a round on the ground?"
I think there's an entire thread dedicated to a tragedy that occurred because movie people often have NO IDEA how firearms really work.