Mac,
I picked up the same gun this year and i agree with you. This gun is awesome. When I first got it I was loading 350 grain Hornady hollow points. Fun, but my shoulder didn't think so after a range outing.
So, I switched loads to a Cast Performance 405 grain bullet over a load of Varget powder. At 100 yards I can get a nice 3" group, and this is with my Williams peep sight. I did slug the bore and I am using the 459 diameter bullet....but my micrometer says they are actually .4585.
The 405 grain\Varget load is eaiser to shoot than the hotter hollow point loads. They also bring down a whitetail without taking out an entire hind quarter.(No expansion of the lead bullet)
Dave.