I bought a DPMS LR308, with the intention of swapping out parts to get it set up the way I wanted, since on paper that looked less costly than buying parts. Problem with that plan was I assumed the factory barrel would actually shoot groups. So along with the parts I wanted to swap, I had to buy a new barrel. The factory chamber was 308 Win, and having a number of 308s, I decided to stick with that, when I ordered a new X-Caliber barrel. I did go with a slower twist, because I want this rifle to shoot 110-150 gr. bullets. Shortly after the order, I got into the 260 Rem., in a bolt gun, and now I wish I would have chambered the new LR-308 barrel in that. I shot a northern whitetail doe(140 lb dressed), this last deer season, with the 260 Rem., launching a 100 gr. Barnes TTSX. The autopsy showed that was plenty of energy and damage for me to consider it a cartridge for up to elk sized game. It shoots flatter, than the 308, and the selection of 6.5mm bullets makes it a good long range target choice as well.
The good news/bad news deal for me, was this X-Caliber barrel isn't impressive accuracy wise, with the loads I have tested. So it is possible that if I get tired of trying to find an accurate load, I order another barrel, in 260 Rem., from a different vendor.
Anyway, if it were me, I would look at getting either a 260 Rem. or a 6.5 Creedmor, in that AR-10. YMMV
Squeeze