Rusty,

P.S. to my last post.

I also considered the data at the Accurate Arms website for the 50-140 Sharps.

They found that 105 gr. AA4350 and 550 gr. lead bullet yielded 2184 fps @ 27,500 psi, less than the black powder pressure of 28,000 psi.

View their data at:

http://www.accuratepowder.com/data/PerCaliber2Guide/Rifle/ObsoleteCartridges/50%20140%20Sharps%20pages%20371%20and%20372.pdf

Again, good luck and good shooting.

CptCurl