The .223 tikkas either have a 1 in 8 or 1 in 12 twist, not 1 in 10. Unless its not a stock barrel. If its a lite it doesn't have a heavy barrel
Have you tried without moderator?
Have you checked scope/mounts?
Is it a new rifle ie, has is shot good groups and gone bad?
Is it cleaned properly?
:stupid:
+ Check that the barrel is floating properly, a piece of paper such as a bank note should fit up between the barrel and the stock. I have a sneaking feeling that the weight of the mod may be letting the barrel come in contact with the stock. Having previously owned a T3 I know