Im having a weird issue in one of my 44-40s. Ive been playing with loads for my 1866 Uberti clone. Ive been trying to replicate my 1250 fps blackpowder loads using A2400. Ive managed to find the sweet spot with it getting 3/4" groups at 50 yards with cast Accurate 43215c bullets. Using 15.5 gr. of 2400 the 1866 is averaging 1270fps. Just for fun I shot these same loads through my Uberti 7.5" SAA and the velocity drops drastically to 500 fps. The bore on both the 1866 and SAA slug at .429 and these bullets are sized to .429. I loaded up a few sized to .430 through this Uberti and it made no difference at all. What is the problem here? I should be getting at least 750 fps out of these loads. Is it possible that 2400 is position sensitive in these 44-40 cases?