I haven't slugged the barrels but was told it wasn't necessary cuz of consistency of known data, so here's my question. All my moulds drop .458" bullets, which I understand to be .001" over groove dia of the 45-70. Just received the 45-90, wh/ was supposed to be .001"-.002" larger bore dia than the 70, but at the muzzle lands at least, this isn't the case--it's actually tighter by maybe .005" but noticeably so. I understand these are just the lands, and that the (relative and/or actual) groove depths of these two rifles may differ. That said...IF I had a .458" groove dia. (wh/ the 90 is supposed to be and may be), and I can't get my bullets to drop at .459", will obturation make up the .001" deficit if I use a softer alloy? Another option would be to beagle moulds then resize for .459" but I'd rather not resize, unless you guys would recommend that as against going from 20:1 to, say, 30:1. (Black powder charges only) Thanks
edit: Just ordered some 3M hi-temp flue tape. Have read that it only adds .002" to the drops. And think that I'll be ordering a .459" sizing die to go w/ the .458" sizing die that I originally got. But first I'm gonna slug the barrels. Appreciate that what matters is chamber dimension, but that's all the more reason to gain some dia. here.
double edit: Rather than beagling for out-of-round bullets/noses (even after resizing), think I'll be lapping if I do anything. Suppose my question is now reduced to how snug a fit I should be after b/t the bullet nose and chamber throat for 1/18 twist @ 20:1 alloy under BP pressures. All I know is that this tiny amount of nose play @ the muzzle lands (of the 45-70) indicates an unacceptably small nose dia., regardless of obturation effects.
edit: Just ordered some 3M hi-temp flue tape. Have read that it only adds .002" to the drops. And think that I'll be ordering a .459" sizing die to go w/ the .458" sizing die that I originally got. But first I'm gonna slug the barrels. Appreciate that what matters is chamber dimension, but that's all the more reason to gain some dia. here.
double edit: Rather than beagling for out-of-round bullets/noses (even after resizing), think I'll be lapping if I do anything. Suppose my question is now reduced to how snug a fit I should be after b/t the bullet nose and chamber throat for 1/18 twist @ 20:1 alloy under BP pressures. All I know is that this tiny amount of nose play @ the muzzle lands (of the 45-70) indicates an unacceptably small nose dia., regardless of obturation effects.
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