Congrats on the AZ elk tag. I drew this year too. First one since 1999. 7E early rifle bull. I have 3 others I will be helping on to try and fill bull tags too, in 7W, late rifle bull.
I will be loading some custom ammo for my buddy in .300WSM in a couple months. Even though I have not had great success with them as far as accuracy goes in other chamberings and bullet weights, I am going to try the .308 178 ELD-X for it. If I can't get them to shoot like the others I have tried, I have 190 Berger HVLDs ready to load that have worked in other .300WM and .300WSM rifles.