Like the title says, if you shoot both a 45 ML and a 45 black powder cartridge gun I may have done something that you can try. I have shot both kinds of rifles for some time, but had to sell my Sharp's 45-70 years ago when I was out of work... Recently a nephew handed me his Shiloh Sharp's 45-70... I wouldn't take it as a gift, but told him I would work up some loads and put some sights on it... well that was my plan. Somewhere along the line I decided to try the Gould bullet (Lyman 457122 330gr HP).. I thought something like that too would be a good bullet for my inlines and caplock... but, being on a limited income I couldn't buy two molds...

I worked up initial loads for the 45-70 that were not very good and put it aside to try to use that bullet in my Knight DISC Extreme in .45.
I got info from a couple of guys on modern muzzleloading forum and Ed Mehlig was kind enough to send me some sample bullets to help me get off the fence post.

Long story short.. I cast the bullets of soft lead, lube them by hand with beeswax/olive oil lube, run them thru a Lee .451 sizer, knurl them between two mill files and go back over them with the same lube... in my Knight they are awesome. Initially when I went to size them down to shoot in the muzzleloader I tried both a .452 and a .451 sizer and didn't like the way they seated in either of them... the .452 was too tight and the .451 was too loose... then I remembered how I used to knurl 12 gauge slugs to increase the diameter slightly and it worked out just right for my rifle. .. I shot them this week at range and using 75gr(volume) Swiss 3F, cardboard overpowder wad from milk carton, heavy felt wad under bullet... they shot great @ 100 yds and shot to shot FPS was excellent averaging 1486 and StdDev of 8.63. And, this morning was opening day of early ML antlerless season here in PA and I took a nice big doe with one of the Goulds at a little over 100 yds.... now have to get back to get the Sharp's figured out... but that should be pretty smooth.

Have fun,