Maybe I'm just getting too old, but I seem to remember some 1000 yd. scores from Camp Perry back in ancient times before computers and special barrels/scopes/bullets, etc. where some shooters were winning with 8" and 10" groups. And I did see a USMC Master Gunnery Sargent, using military Springfield '03 place 5 shots inside 10" at 800 yds using USMC match ammo. That ammo was basically 165 gr BTs at about 2750 fps. Oh, BTW, he was using the original '03 peep sights.
Find the load your gun likes the best, using the highest BC bullet it will shoot best, and using a 48" wide x 72" tall target,and the same point of aim,(place your aim point at the top 2" of the target) start at 100 yds, move it to 200, then, 300, etc. until you get to the distance where you are unable to hold your shots within the potential lethal area of the intended game (deer = 12", elk = 16", moose = 18", etc). That's the max range you should consider, anything else is a crap shoot, you miss or wound and not recover the animal.
And remember, practice, analyze, and then practice a lot more. Don't be too quick to start making wholesale changes until you are certain sure that changes are necessary.
Just a quick note/idea - did your smith check the crown on your barrel?
best of luck,
Rick