The load I've been using in my Tikka T3, a limited run from Whittaker Guns, is 45.0 RL-23 with the 140-grain Nosler AccuBond, which gets about 2700 fps from a 22' barrel. (It also works very well with the 140 Sierra GameKing, but AccuBond will exit 6-point bull elk with rib shots at 50 yards.)
Guess I don't see the point in using bullets lighter than around 140 grains in a 1-8 twist 6.5mm. For all practical purposes they shoot plenty flat, drift less in the wind lighter bullets, penetrate deeper. and ruin less meat. If you're going to use lighter bullets, why not just go with a .25--or even 6mm?
