...So "as far as you can tell" the factory tunes a hunting rifle, for use with an old match bullet??......

For grouping that close (200) no way would I be using boattails, hasn't had enough time to go to sleep yet.
Without specifics, no one can offer load advice.
Are you full length sizing or neck? Are you trimming, how much jump are you trying, how much have you tried, what powders have you tried, which loads in each?..... Is the barrel floated, is the action tight, is the scope tight, is the scope verified...

My car doesn't run. I've tried everything, you name it, can someone help me with what to fix?

Same question and detail