I used to load a lot of nickel plated stuff for waterfowl. Imported, made in Italy. It was quite hard, but I do not have any numbers. Ballistic Products used to sell it. My favorite was #3s - possible Nash Buckingham bias. For me, it patterned better, avg. improvement was 2% to 4%. Winchester and Remington used to custom load it for the U.S. Olympic Team.
Despite what makes sense, and what we all heard for all those years, sphericity doesn't seem to matter one whit, based on the results Hevi-Shot gets/got in all the competitions. Ever look at Hevi-Shot up close ?
