I have one and it is one of the best rifles I own. Tornado Tech re-threaded it attached and indexed a AAC muzzle brake for my 762SD. Combined with my Leupold Mark 4 LR/T and a harris bipod I would have to say it is one of my favorite. It will hold great groups with a wide range of factory ammo.
I see that the Tikka T3 Tac thread is M18 x 1 and AAC offers an 18T flash hider in that thread but AAC doesn't have any stock. Is that the reason you had the barrel rethreaded?