Hi Mousemann
My 1858 Pietta Remington 44 Stainless - likes 457 ..
I was using smaller balls (451) - as it was a struggle to get them in - so I did not dare try bigger - then it turned out that the lead I was casting from was not soft lead - but had a little antimony in.
Changed to soft lead - 457 goes in beautifully with a nice lead ring cut - which means more flat on the rifling = better groups !!!
My grouping improved as soon as I moved to 457
Wish you were closer - you could try mine gladly !
Oh - just realised = 1000 posts !! where did they all come from !!
Cheers
Roy