I have an AXMC Long Action with 300 WM, 308 Win and 6.5 CM barrels.
I run it in comps with 6.5 CM. No problems. With habdload it shots one hole at 100 yards.
I hunt with the 308 Win for white tail deer.. all DRT.
For Muleys and Elk I prefer my 300 winmag barrel.
I have other custom rifles...
The bullet flight tells the truth...always with good ammo.
The challenge is to shoot at a given point, watch the splash, then when conditions are similar make the appropriate holdovers.
If you shoot under different conditions from the splash...fubar.