Brent has a photo of a original Sharps long range bullet on his website.
http://www.public.iastate.edu/~jessie/PPB/PPB.htm
Looking at all of the sharps, metford, Gibbs they are all pritty close.
Buffalo Arms has a new bullet that is Identical to what Brent has on his website.
Your picture of your bullet looks a lot like the Metford Jim and I worked on back in 08 when he started making moulds. I think I still have the drawings on backup and the mould is a two hole guide pin mould. I had him make one for the .442 and .492 for the 50.