Hi all, if the gun is English, be wary of nipple thread size. Most percussion era English nipple threads were 1/4" BSF 26 tpi, this does NOT correspond to the thread of 1/4" UNF which has 28 tpi and a different thread form. I have tried to buy BSF nipples from TOTW in the past, but they only stocked UNF. Hope to this saves someone graunching threads!!