I just started loading for my Tikka T3 6.5x55. While it's primarily a deer gun, I have been playing with Match loads. Best results today came from:
139 Lapua Scenar
Win Brass/Primer
46.5 gr RL22
3.012"
Group size: 0.6"
c.2550 fps
Another good load:
142 Sierra MK
Win Brass/Primer
46.8 gr RL22
3.012"
Group: 0.76"
c.2540 fps (only chronoed 3)
The RL22 seems to work better than the RL 19, although I also changed bullets. The Speer 140 SPs I'm using for my hunting round don't group very well at all (c. 2"), but they'll get the job done. I'm planning on working up a load with the Sierra Gameking 120 and 140, which should group better.
As for Varget, I'm going to give it a try with 85, 100, 107, and 120s. But overall, I think it might be a bit quick for the 6.5x55. We'll see - it's the best powder I've used for .223 and .308.