bull nutria: reading your posts sounds exactly like what i went through when i purchased the exact same rifle season before last. what i finally discovered, after chasing groups all over the target, was that my problems could all be attributed to barrel heat. i would get a cold bore shot in one place, then a group in another place, then a pattern all over the target as the barrel warmed. this is at 100 yds. if i just sat down and started shooting at 50 yds, i'd have ugly 2-4" groups like you are describing.
my solution was to sight in for the cold bore shot. took forever, cause i had to let the barrel cool off completely between shots. but now i have complete confidence that the 1st shot will be dead on the money, and have some targets and a deer to prove it.
it is disappointing to me that i can't just take the rifle out to the range and plink with it, but i have confidence in it as a single shot hunting arm.
might work for you, might not, i just suggest giving it a try. the load i use is a full charge of H110 per the hodgdon manual, 240 g XTP, magnum CCI primers. put a crimp on it, too.