You bring up a good point about the .454 balls. I have a Lee mould and found that the first .457 balls I cast, which are a little on the hard side, at least 20:1 tin, perhaps even higher, take a lot of effort to load. Pure lead is no prob. But I seem to get really great accuracy with the slightly harder round balls, better than with pure lead. I don't shoot light target loads, but prefer a full cylinder of 3F, enough to just seat the balls flush. I'm considering trying Triple 7 for more velocity, where there should be an advantage to the slightly harder alloy if they start hitting the 1100+ fps range. I'm thinking about getting a .454 mould for casting the harder round balls.
Oh, btw, great looking Old Army, stpetejoe. The high polish finish is stupendous! You will scarcely believe how much fun, and accurate, they are until you shoot it.