I can't speak to belted magnums specifically, but every factory TC barrel I've seen, and most I've heard of, are capable of MOA accuracy with a bit of tweaking of the load and minor, inexpensive or even free tweaks to the rifle itself. There are exceptions of course, but as Ladobe said, TC's warranty is among the best in the business.
As to the self-proclaimed "master" of the Encore, some of what he says makes sense, but much does not. I wouldn't exclude him from my research on the Encore, but I sure wouldn't stop my research there either. Some of what he advocates is down right damaging to the rifle, and some is even dangerous (which is part of the reason he's been banned, as I understand it).
You've come to the right place, in my opinion.
Just a Shooter