Stopping a zombie can be a messy business. Where I’d love to be able to keep my distance and pick them off over time, the fact is, characters often get into close quarters and trapped with the living dead all around them. Depending on the situation there’s no telling if more ammo is ever going to come, so a few hand-to-hand tactics like stomping could really come in handy in those dire straights.
In this case the zombie has to be on the ground. I’ve illustrated this as a crawler but any old zombie will do as long as it’s on the ground. Be careful getting near it but do your best to stomp the head. Depending on the level of rot, it might be possible to just kick the thing in the head and be done but the skull can be a surprisingly tough nut to crack. Go for the part that seems most vulnerable on your zombie. I’d say as long as your boots are sturdy crushing the mouth or breaking the jaw is a good way to buy yourself a little time if you aren’t up to actually destroying the brain with your boot. (And who could blame you? That’s GROSS!)
The real disadvantage here is that you really do need to be in close to the zombie in order to make this work and safety really calls for keeping ones distance. So again, I wouldn’t recommend this as my first choice. Then again, if you’re trying to conserve energy and ammo, a good old fashioned stomping might just do the trick! (Just remember to never do it on the living!)