Mine is also is 6.5 creed. A friend gave me a 308 20" AT barrel that I know shoots tight. I may send it out to get it cut flush to the chassis for hunting.Mine was in 6.5 creedmoor and consistently shoots 1/2moa or less depending on conditions. I shoot norma golden target ammo which is cheaper match ammo but it bug holes. I like the heavier legacy action. I bought a bartlein and a proof .308 barrel for a shoot off and they shoot the same accuracy wise for me.
I would not buy the at-xc over the at-x. I just don’t feel there is enough to justify it for me. Definitely not for $6500 good luck I know you will love the accuracy.
I don't see anything on the AT-XC worth doubling the cost. That being said, some AT-X parts are perpetually out of stock. Parts that the AT-XC already has. That alone may be enough to convince the consumers.