As near as I can tell from the data that I have seen, 1865/75.
I have some MagTec cases, new, that are just a little lose in the chambers un-fired. I agree that a larger ball may be needed but BP should expand a pure lead ball to groove dia. For now the .760" ball will just go into the new unfired cases.
5 to 6 Drams of BP will require a filler of wads to fill the case above a powder card that the "ball" can sit on.
Your suggested starting load was were I also figured to start trying to see what will happen with regulating a R & L @ 50 to 75 yds.
Life is a little busy now with some "court proceedings" going on but I'll let you Gentlemen know what happens as soon as I can get started "playing" with it. Thank you for your interest.
