I load .457 round balls with 13 GR. of Unique. With the longer barrel of the BC, a lot of the lower loads don't get enough oomph to get to 25yards well. I started at 6 gr. Unique and laddered up to 13 gr. At 6 gr. the ball rolled out the end of the barrel, literally. Anything higher than 13gr will lead from my experience. I settled on the 13 gr., because it gives good accuracy and consistency in this barrel length. I can almost always hit the 10x10 gong on my range at 100 yards, and group around 6" on paper at 100. That's pretty much max range, because the accuracy seems to destabilize around 100 yards. At 50 yards, I can hit a pop can size target well. The lowest load I'd use for varmint size game is 10gr. That is only good to about 50 yard max and isn't quite as accurate in my gun although it is a lot quieter also. Just remember, this isn't really intended for hunting medium size or larger game, but a way for me to plink and shoot small game while on a big game hunt without having to carry a second weapon. I'm working up some shot loads to try also, but really trying to avoid leading and the length of the barrel seems to really limit the range due to the rifling. Only good for about 20 ft. thus far. I intend to try some bismuth shot loads when I can get some as this should help avoid deposits. I have started to work into some ball loads for my .45 LC also, but cannot test them until my original gun gets returned from the dealer.
In order to get good accuracy, the process I use is to use once fired brass and DON'T full length resize the brass. If you don't have one, I'd recommend getting a Lee Classic loader. I deprime on the classic loader base and thus brass isn't modified. Since these are low pressure, I set the same 30 or so aside only for RB and you don't get much case stretch, since it's so low powered. I still put them on the length sizer gauge to be sure, but I haven't had any move after a few firings. If your chamber is big enough that the fired brass allows the ball to fall into the case, as mine does, I then tap it into the classic loader, which neck sizes only, and it doesn't even require much pressure. If your chamber is tight enough to make the ball hover on the edge, you can skip that step. If you do neck size, I bell the mouth slightly with the tool supplied with my .45 LC Classic loader. This puts a slight bell and lets the ball hover almost at it's hemisphere. I then use my hand press, also a Lee product, and use the expander die as a seater. To set it up, I put a case with a ball in the mouth into the shell holder and screw it down until it just touches the ball. Then I lower the case/ball and screw the expander die in 1/2 turn more. Then run the case/ball back up into the expander die. This seats the ball just a fraction past it's hemisphere and doesn't deform it. I have "thumbed" some in place and just tapped them with a plastic tipped hammer, but the accuracy was not nearly as good. The final step is to then use my Lee Factory crimp die and set it per Lees instructions, which are to screw the die in with a shell in place until it just contacts the mouth of the case, then lower the case and turn it 1/4 turn more. I think I actually use closer to 1/2 a turn in this case. This basically crimps the end of the belled area just enough to lock the ball in position and lets it build some pressure before entering the bore. Since there is a small 1/8" or so jump to the rifling, I think the crimp helps bridge this better. I've actually been considering buying some .45-90 brass and trimming it to full chamber depth for these loads and shot loads, but still having fun testing them.
I keep about 5 of these on me when going out to hunt and if I see one of the despicable woodchucks, that seem to love my families' homestead, I pull out one of these and it will dispatch them quite nicely. I have been considering going to a color marker code on the balls and carrying a few 10gr. loads for the occasional fox squirrel that seems to think it is his job to notify the forest of my arrival too. I think markering the tip red for the higher power balls and blue for the lower power will let me tell at a glance which is which. The next set I load up, I've been considering giving the balls a thin coating of Lee Liquid Alox to test their accuracy.
If you try them, just be sure to check the bore after EVERY single shot for a stuck projectile. This would really ruin your range trip if you don't. I also keep my muzzleloader range rod on hand in case something is stuck. The range rod is sturdy enough to push out the stuck ball with the loading Jag attached and is made of aluminum, so it doesn't harm the chamber or barrel. Hope you have fun if you try them.
*edit* I have done 2 and 3 ball loads, but was very disappointed with their performance. It's really hard to do it with unique, but with BP where you can seat on the powder with the first ball and a wad, it might work better.
