I'm running a 6 Ackley on a Sako 85 and I love it! It comes very close to the performance of my dad's 240 Weatherby. My only drawback is that I rechambered the factory 243 to the 6 Ackley and it only has a 1:10 twist so I'm limited to 90 grain bullets and less (except 100 grain speer boat tail and 95 berger classic hunter stabilize still) It is definitely worth the time to form your brass from Norma 7x57 so you have better brass. The brass never seems to grow. Another thing I like about the 6 Ackley is the long neck since I believe will keep the flame point inside the neck rather than the throat and will help barrel life. As far as 3000 fps with a 115 bullet that is childs play haha. I have been running RL 26 in mine and had great speed and accuracy. Since I cant stop tinkering I will be playing with some Retumbo, 8133, RL23, and possibly RL16. When its time for a rebarrel I will be going to a 7 or 7.5 and will be shooting the Nosler 105 RDF and 110 SMK. The bc on the 110 is HUGE!!! I shoot both of those bullets in a 6 Dasher and they are incredible.
You cant go wrong with the 6mm Ackley!