In the much older traditions and "real" stories there is no clear delineation between werewolves, ghouls, and vampires. It had more to do with the fears of the people in a certain locality than it did with a specific type of creature.
Many methods were though to work on almost any creature if you could capture it: decapitation, fire, nailing the creature to the inside of its coffin, even convincing a priest to bless the grave of a restless spirit who was buried a heretic.
Later stories, books, and movies started to make the difference clear:
Werewolves were alive, and overfilled with inhuman desires. Pure things like silver, and roses could control or harm them. Strong medicine like wolfsbain could ward them off. Charmed/pure food would reveal them if they were your guest and biding their time. They would rape and rip as well as kill. They were cannibals.
Ghouls were humans who ate dead flesh. They were sad and stinky, and needed to be destroyed like a sick animal.
Vampires were dead and soulless. Their bodies must be dismembered or sealed into the coffin with a stake or holy relics. They did not fear or even care about anything except to fulfill their appetites. They often left their victims drained and weak for miles around the grave.
In modern lore, the line has become blured again. Silver has become a universal like decapitation and fire. Groups are often lead by a cold and calculating vampire who has a fiery werewolf to do his bidding.
Blessings do not seem to work on either (unless you "really" believe) but enough firepower will slow them down even if they eventually recover.
. And, is it the silver that has an affect or the fact that its a bullet - I know an ordinary bullet wouldn't work, but what about like a silver earring or something?