Conical bullets for muzzleloading caplock rifle, about .38 caliber

[lobogunleather]

I own an original late-19th Century Pennsylvania caplock sporting rifle. Bore diameter is .380" to .385", groove diameter about .410". Shoots quite well with patched round balls (.375"), grouping about 5" at 100 yards when I do my part well.

I would like to try conical bullets but the somewhat unusual bore diameter makes mold selection a bit difficult. The Lee 375-130 Conical mold (for .36 cap & ball revolvers) looks like it might work, but I am curious to find out whether or not the bullets will obturate sufficiently on discharge to engage the rifling properly.

Anyone with experience or ideas to offer? Your input will be appreciated.

[rodwha]

I'd take a look at Accurate Molds to see what he has, and if there isn't anything you can have him come up with something.

That's really cool! I've been wanting a rifle/barrel that I could use .375" pistol RB's through. Hard to find, but I'm thinking a .40 cal might work with 0.016" pillow ticking patches.

[Good Cheer]

I own an original late-19th Century Pennsylvania caplock sporting rifle. Bore diameter is .380" to .385", groove diameter about .410". Shoots quite well with patched round balls (.375"), grouping about 5" at 100 yards when I do my part well.

I would like to try conical bullets but the somewhat unusual bore diameter makes mold selection a bit difficult. The Lee 375-130 Conical mold (for .36 cap & ball revolvers) looks like it might work, but I am curious to find out whether or not the bullets will obturate sufficiently on discharge to engage the rifling properly.

Anyone with experience or ideas to offer? Your input will be appreciated.

That's about .025 or more? That's gonna be a whole big bunch to get a relatively light weight bullet to expand and be accurate.
Maybe a hollow base something like one of the old Lyman / Ideal designs?
http://i791.photobucket.com/albums/yy192/SNARGLEFLERK/386179_zps244d3a3b.jpg (http://s791.photobucket.com/user/SNARGLEFLERK/media/386179_zps244d3a3b.jpg.html)

Have you measured the twist yet?

[waksupi]

You might try a crossed paper patch. See Ned Roberts book on the Cap Lock Rifle.

[Baron von Trollwhack]

You might even try a very thin cloth patch, that feels like loading RB. BvT