RB Size & Load Specs. for a .440 Rifle... Looking for YourRecommendations

[Collector]

Subject just about covers it.   

What have users of this rifled caliber found to be  their most effective/accurate loads?

Thanks in advance!

[Daryl]

With a .440" bore size rifle, I would likely use a .433" ball. Seems to me, Lee actually made some that size, which is why I mentioned it.
Otherwise, I would be looking for a .435" ball for a .440" bore.

[Hungry Horse]

 A lot depends on how deep the rifling is. Ages ago, when the vast majority of modern muzzleloaders were imported from Europe, some were .440 bore diameter, but the rifleings  were very shallow. A .433 ball would only fit with a patch that was too thin to be of any use. I had one of these guns, and had fits with it. I finally found a .429 ball mold, and everything worked fine thereafter. That gun had very shallow cut rifling, and shot like a dream as long as you swabbed between shots. I’ve always thought that shallow rifling may be the source of the problem, that led the old timers to swab after every shot.

  Hungry Horse

[Collector]

The barrel will be custom spec'd so I'll be able to have the advantage of the barrel maker's expertise on the rifling depth.

I'm usually looking for 'not exactly standard offering' calibers in some of my builds.

My preference has generally run in the smaller RB/thicker patch combo, although in looking at RB molds for this caliber, they were all over the place, running from .424 to .437 in diameter.

[hanshi]

I have a rifle from the early 1960s, putatively a .45, but actually required a smaller ball than true .45s.  It came with a mold for, IIRC, 435".  I used thin patches but it still shot well.  Later I tried a .440" ball and it worked with the same thin patch.  Seating wasn't much more difficult than with the smaller ball.  But it balked at a thicker patch and no way could be loaded with a .445" ball.

[smylee grouch]

Why not slug the bore and find out the exact bore size and grove depth.