I'm using DDEPP (double diameter elliptical paper patch) bullets designed by Arnie/Beltfeld for my Sharps (excellent results), but some months ago I acquired a Pedersoli Gibbs and decided to use the same DDEPP bullet sized down to be loaded correctly in the 36" barrel. After adjusting the paper thickness and the bp loads, I found that this extraordinary 525gn bullet shoots very well both with my Sharps and Gibbs. In the attached picture you can see my last target at 200 meters and 3" x 1.5" grouping with the Gibbs and another 4" x 0.5" group with the Sharps.
Thank you very much dear Arnoldo for these results, 1 bullet for 2 different rifles!