I know 2 or 3 very good shooters that use the 2 1/2 primers consistently, neither of them use a Sharps, but are shooting hi walls custom built. Maybe they modified the firing pins on those? Don't know, but I do know it's going to be an uphill fight to best them on the score board.
Awe yes those little devil winds, maybe unseen thermals,, lots of things can wreck some pretty good groups that aren't seen until after the bullet impact shows up.
Jim as you spend more time, and tweek the loads a bit here and there, you may end up wondering why you need any other cartridge.
A wise man can always be found alone. A weak man can always be found in a crowd.