Has anyone tried Lyman 533476 in a 54 Sharps?

[Bouteselle]

Gentlemen,
in a few months I have a long range contest, and I wanted to use my Shiloh 1863 infantry rifle.
Yesterday I did some tests, I'm pretty happy with my paper cartridge, perfect reliablity, not too much fouling, but... catastrophic results on target at 100 meters. Yet I used a pretty 470 grains, 544" bullet, from an artisanal mold, and I was very confident. My barrel is 540", nothing to report...
At 50 yards it's not awful yet... but at 100, a C200 target isn't big enought. I conclude that the bullet is quickly destabilised.

In order to save time, gasoline and powder, has anyone tried the Lyman 533476 Minié bullet in a Sharps?
In pure lead they come out my mold at 535", but they seem to well fit the chamber.
I only have these two molds.

[Abert Rim]

Sir, if you don't get the answers you need, consider heading over to the n-ssa.org bulletin board. Lots of the Civil War skirmishers there run the Sharps percussion rifles and carbines in serious competition.

[Bouteselle]

Thanks!