Some things to check to make sure it's not the rifle, and you probably know these already, but just in case...
1) Make sure the barrel is free floated all the way back to the receiver.
2) Ensure the action screws are torqued to the recommended value. From the factory, I think it's 35 in-lbs, which I suspect would be the same for the stock you have there, unless it came with instructions that say differently. Here's a discussion on the recommended technique for reattaching a barrel assembly:
http://www.tikkashooters.com/public_html/gunsmithing/tightening-the-action-screws-on-a-t3/
Note that the 51 to 52 in-lb torque mentioned in the initial post seems quite high unless you're using an aluminum chassis instead of a traditional stock, so I'd stick with the 35-ish range.