I used to cast round ball for my 32 and 36 caliber black powder pistols but gave that up as buying buckshot for projectiles was cheaper and easier. I still have the molds but it is probably even more expensive these days as lead wheel weights aren't as easily found as they once were.
For "close" coyotes I found lead BB and even #2 birdshot to work much better than any buckshot. #4 birdshot and #4 buckshot tie as a distant third place. The larger sizes do not even make the cut for me as patterns are just not there. I liken them to steel F shot for pass shooting geese. The "magic" pellet was spectacular to see but there were many gut shot birds that sailed off. Out to 40 yards I expect a dead coyote when I do my part with my chosen loads. These loads are buffered ones from Tom Roster's manual from back in the days lead was legal for waterfowl. They put the hurt on geese and cranes well beyond the norm and do pretty good on coyotes closer in.
