When does the Wormwolf sleep? At night, like everyone else, and that is exactly when the reckless shooting most bothers him. It really is very dark out there and John would be in so much more trouble than he already is if he didn't bring a torch with him. Heck, all he needs now is a pitchfork!
Then again, it's probably best to stick to the ol' boomstick when it comes to getting rid of them Wormwolves.