I didn't try it out yet, but I read some posts on
www.muzzleloading.com that "TRESO" nipples should be the best. They are sold by thunder ridge (I think) for $3.00 a piece. As I have some problems with my Uberti factory nipples (caps #11 too large, caps #10 too small, RWS caps #1075 too expensive and still too large) I'll try out the Treso brand.