Its not big but there are clubs that do it. I shot a 3 gun cowboy action competition this morning - percussion revolvers, shotguns, and lever action rifles.
Video of a stage being shot,
http://www.youtube.com/watch?v=Rdvuc_q6O2Q
Some pictures,
http://i201.photobucket.com/albums/a...oll_2007/4.jpg
http://i201.photobucket.com/albums/a...oll_2007/2.jpg