You might think about this. Bore the chambers in the cylinder .450 dia.
The groove dia of the barrel "The widest part" .448. The bore "measuring
across the lands" .440 dia. If I did this right, this should give you a depth
of .004 on each side of the barrel. You would use a .454 dia ball.
This is based on my custom .36 cal Remmy. My chamber dia. is .357. I use
a .360 ball. My groove dia. is .355. Hope this helps. Oh my rate of twist
is one turn in 14.