I have a H&A repro underhammer in .36, the .34 ball is only 50gr and gives 1 1/2 " at 25 yds.
I modified 105 and 150 gr wad cutters into hollow base conicals by boreing the bases out in my minilathe , the bullets, lubed with LBT soft blue or liquid alox, give me 3/4" or smaller groups at 25 yds at 1400 fps with 35gr 777, the 150, now 130gr and 1500 fps , the 105, now 85gr. bullets with 30gr 777.
A real improvement over the 50gr ball.
Don