For the best LR performance, I would get a PTG or Wyatts Bainey box (3.110" internal length) and run a .260 AI throated proper for whatever bullet you prefer to shoot and get the most out of it. If you aren't about fireforming, the same setup but strait .260 would be great. A 25 creed sending the 131's would be pretty impressive as well, and would run fine on the setup you currently have, or a 6.5x47 as others have mentioned for the 6.5 flavor (simply because of the stigma surrounding the 6.5 creed....it is a good round though)......depending on what barrel channel the stock is inletted for, I would look at a #1 or #2 fluted 22" barrel. This would be a great back country mule deer or sheep/goat rifle for sure. Chamber preferences may change if the quarry is to include elk frequently.