I have a T3 in 270 WSM and it also shoots clover leaf's all day long (as long as I do my part...which isn't every day). I found it shot all four of the the varied "test" loads I built for it when I first got the gun...the worst group was 1.75" (and it was a new rifle and the first time I had shot it)...I agree with others, in that I would first, swap out the factory rings/bases (I didn't much care for the factory rings and replaced with Lupy rings and bases)...and also try a different scope...I have more than once had a scope on a used rifle be bad...I too would also try different ammo...IMO opinion the two choices you used represent the far cheaper end of the spectrum and I have never really seen good results from core-lok's...except in one of my 30-30's.