I have not tried it, but I hear H1000 powder is *magic* in the 6.5x55. Maybe you ought to try it. My Ruger shoots fine with either H4831 or H4350 so I have no dog in this hunt.
I hope and pray you find a load you like with a bullet you like.
Our God reigns. Harrumph!!! I often use quick reply. My posts are not directed toward any specific person unless I mention them by name.