I had a 6.5/284 made up on a Mod 700 Short action once. I seated the Nosler 125 Partition and the 120 BT to 2.780 and never had a problem. I shot antelope/deer/extocis such as Axis deer, Fallow and Blacbuck with it. I always got complete pentration and, as said, DRT performance. As this was a hunting rifle, I felt no need for heavier bullets. If I had kept the rifle ( I traded it to a friend ) and wanted to shoot elk, I would have used the 125 Partition or, most likley, a Barnes XBT ( pre TSX days) It is an awesome little round.
I would some day like to try out a 6.5/06 Ackley in a 24" bbl, maybe 25" just for grins. I have a friend down in Texas who has an original Mod 700 BDL in .264 Winmag. He bought it used from a mutual friend of ours back around 1980 and he is still whacking whitetail and hogs with 140 Partitions. I can still remember when many guys used the 6.5 "Eye-talian" surplus rifles and those long 160gr roundnose bullets for deer/hogs. Real killers.