A few things, Deand:
Are you shooting real black powder or a sub? My friend's CVA doesn't group nearly as well with Pyrodex or 777 as it does with Goex or Kik. His also groups much better with lighter loads than full-house ones. 80-90 grains sounds spot on and will take any deer on the planet with proper shot placement.
What diameter ball and what thickness patch are you using? His does better with a .010"-under-bore-diameter ball (.530") and a thick (.018"-.020") patch. If you're already using this combo, you might try a .005" bigger ball (.535") and a thinner patch (if the thicker patches are too hard to load...otherwise stick with the thicker ones).
What are you using for patch lube? It can make a tremendous difference, believe it or not. I've seen outstanding results from Hoppes No. 9 Plus in a wide variety of guns and I've heard excellent things about a couple of the homemade lubes from the forum here (moose milk/snot and cat whiz).
What are you cleaning with? If you use the wrong product, the resultant residue can be almost impossible to remove and can tear up patches during loading, thereby hurting accuracy.
Are you shooting off a bench? If so, are you resting the barrel or the stock on the front bag? Groups can quadrupel in size if you apply excessive upward pressure on the barrel.
How many shots have gone down the bore? My buddy's CVA didn't shoot for beans until he'd fired over 200 shots. Then it was like magic; the groups shrank every time he had the gun out for the next couple months and ended up being more than acceptably accurate...about inch and a half groups at 70 yards.
If you're not shooting off a rest, you should, at least for load development. And when you do, try resting the place on the stock where your off-hand will end up when shooting in the field on the bag and only let the weight of the gun keep it there...don't bear down. After you've found an accurate load, shoot it offhand and make any needed sight adjustments...sometimes a gun will shoot to a different point off bags.
And if the muzzle crown is damaged, a gunsmith won't charge much to recrown it, and if you want, you can do it yourself. (Brownell's sells laps and cutters). It's a very easy and quick job.
Don't get discouraged, pard. Load development is half the fun of muzzleloading. Just look forward to that moment when you'll hit on the right combination and your groups will shrink down to bragging size.
:thumbsup: