I would appreciate some advice regarding a custom build I am considering- a 6.5x284 vs a .260 Ackley Improved. I intend to use the rifle out of a stand for deer hunting and afoot for antelope. Maximum shot length is 300-400 yards. I hand load for all of my rifles and will be doing the same for this build. I anticipate that I wil load 120-140 grain bullets. Any load advice would also be appreciated.