Kirk.. if you're shooting maxiball out of a T/C Hawkins what I would do is start on a clean barrel.

Load some Pyrodex P ... about 70 grains. Put a wad between the powder and the flat bottom of that conical. If you have no wads, pour your powder, tap the butt of the rifle on your toe to level the load, then dump 20 grains of corn meal (tea spoon full)on top of the powder. Now seat that maxiball and try that. It should tighten up your groups.

The Pyrodex P is a hotter powder then RS and will get that conical moving faster up the bore of that barrel. The wad or corn meal will protect the bottom of the conical and also help so you don't get blow by in the charge..

There are other conicals out there to try as well.