Muzzleloader is a round ball shooter most of the time for me. So, I like the .54 cal. Still pretty weak compared to the 30-30.
I just bought an older Marlin 30-30 to use hunting. I feel a little safer with a backup shot for bear since i'm an old fart who hunts alone, and we can't use bait, or dogs. On the ground face to face is fun stuff.
I'll use it for deer and elk too. Use a peep sight, and keep shots under 75yds.