I had a similar episode recently that i mentioned in another thread.
Was gut & rear end shooting bunnies at 250-300 yds--that equates to 4"-6" misses or the rifle going from half MOA over the bonnet to 12 MOA between firings
, & was also missing shots at 100 with another rifle where i was trying to hit them in the brain
i was left scratching my head. Turned out it was the action screws--& was on 2 rifles as well...!!whats the chances of that happening in one hunt
one had loosened off, but wasnt "loose" by any stretch.!!, & the other had worked its way to less tension as a result--but again, neither were "loose" But was obviously loose enough to allow a little movement of the barreled action in the stock under recoil.
Check everything on the rifle, from all optics attachments, action screw tension & how the barreled action sits in the stock.
Ive had issue once before with Tikka T3 not performing correctly after a good strip & clean, & it turns out the recoil lug wasnt seated quite right so i was getting weird results.
So now I give mine a whack on the ground with the butt holding the barrel while i tension the screws up (with part tension) then do up to required torque, just to ensure recoil lug arrangement is seated nicely.
Short of that, how old is the barrel...?
I got the most amazing groups with an old 22-250 just before it went awal & the barrel was finished.
Hope you get it sorted.