I have had 2 10" twist 30-06 barrels and both preferred the heavier bullets to the 150-155 class. I had good luck with the Sierra 180gr SBT, and it performed great on deer.

Maybe I am misunderstanding you on this but, are you saying that if a rifle can rechamber a piece of brass that it just fired that the chamber is loose? I have yet to have a rifle that wouldn't rechamber its own spent brass.