Well as a Beretta Rep, I can tell you that each and every Tikka is test fired to verify the 3 shot accuracy guarantee. If it does not meet the required accuracy, it is returned to the production line. So I would suspect the scope.
I sent an inquiry to Beretta to see if they could supply me with the bullet weights used for accuracy verification. Will let you know when I receive an answer.
For the .243 I would suspect they used either 87 or 100 gr bullets.