Just to add
:
Best way is to keep the bottom portion of your body still and snap out/in using your upper body; that way your not sticking a foot out to plant on before you can see them and/or shoot back.
Come out with your setup centred so by the time you can see you're also in a position to shoot; come out with your gun first you're presenting a hard surface over which a posted player will cream his pants over, before you can see him and shoot. Conversely (sp?) come out goggles first, all you're doing is presenting another hard surface on which to score sure hit, before you can shoot.
Posting, just to clarify is when one player gets the upper hand in an exchange of snapping, takes the oportunity and stays 'snapped out' of his bunker putting supression on your bunker, perhaps stopping to make it look like he's reloading, luring you out and gogging you.
Snapping is all about 1st shot accuracy, if you're snapping out/in on a guy posting on you but hitting a bunker 5 feet to the side of him he is going to stay there and not budge; on the other hand come out and hit his bunker 1st time every time, he's going to think about his posting; handing you the advantage.