An interesting target. Some of the wads might help. Especially when you noted that the patches were shredded and burnt up. This could be the Triple Se7en powder doing that. The shredding could be a sign of a ruff bore. If you have no wads, try dumping the powder, then tap the load level, and add 20 grains of corn meal and then the patch and ball. That would also act as a wad.

Another thing I would try is to kick up the powder charge. A lot of times some rifles just shoot better with stronger powder charges.Also some of the new rifles take a time to break in. Maybe not so much with the new rifles like the rifles of old, but still some of them are ruff in the bore and need to break in. So I would not get too worried at this point of an 8 inch spread. I would just keep shooting and trying different powder charges. Sooner or later you will find the rifle's sweet load. If the rifle were at my house, I would kick that powder charge up to 90 grains of Pyrodex RS and a patched ball and see what happens. Pyrodex RS is a very consistant powder in most rifles.

If you have some JB Bore Paste try scrubbing the bore with that. Some people use Jewelry Polish and do the bores. I know one fellow that used to scrub the bores out with Comet Cleanser. All of these will help to smooth out the bore if it is ruff, and get the rifle shooting tighter groups sooner.