Originally Posted by Kevin Cram
It appears that you do have a out of round chamber according to your test. If the threads were cut out of round to the bore then when tightening the barrel nut your not getting even contact between the receiver face, recoil lug and barrel nut more than likely creating some stress. It sound sas if the whole barrel is jacked up. Rather than spend time beating your head against a wall trying to make it shoot I'd tear the barrel off and get a good aftermarket barrel for it and go from there.
If you can't rotate the brass without it not chambering you
need to stop wasting your time and money. also it looks like the chamber is loose (To large)
near the case head because of the ring on the case near the back.
Shillen sells pre chambered barrels for the Savage and with the cost of ammo/components to
load it will be paid for in no time.
There are other barrel makers that sell pre chambered barrels also.
This is a very accurate round and should shoot well under 1 MOA with a good barrel and
J E CUSTOM