I remember watching a movie a long time ago where a town began to be terrorized by some type of wild west type undead character. they never were able to kill them until someone slipped up and told the "heroes" that if they used the old west guns. and not there modern day fancy pistols they could hurt, injure, or even kill these "cowboy ghosts" that's all i got, can anyone answer, thanks.
Ghost Riders may be the film:
http://www.imdb.com/title/tt0235424/
I'd Have to say it sounds closer than anything i can find, but there is so little info out there about this movie who knows....
They mention old guns in this short review of Ghost Riders: http://www.mrsatanism.com/movies/ghostriders.htm
Kroogur probably nailed it.
Purgatory .. the movie not the series
Or it could be Ghost Town (1988).
IMDB Page: http://www.imdb.com/title/tt0095215/
Purgatory
http://www.youtube.com/watch?v=ByiYC1q_IC4&feature=related