Gee, Truckn, it has been a while since I shot LR, but I distinctly recall the Palma types, (also Match Rifle, and Any-any sling shooters) getting 1000 yd targets with 20" ten rings and 10" X rings, while I had to struggle to hit a 10" ten ring just because I had a bipod on my F-T/R.
Have they changed targets because it was getting too easy?
Rob, I recall zero target shooters with .25-06.
There is not the selection of high BC bullets for .25 that there is for 6mm, 6.5mm, 7mm, and .30 cal.
Also the case is over bore and barrel life would be short.
I think a .257 Roberts or .25 Souper would be about right with a heavy boat tail and enough twist.