The SAAMI pressure spec for the 7mmRM isn't near the top of "safe" pressures in modern bolt guns. As others have said, seating the bullet closer to the lands will boost pressures more. You could even back off further, and reduce pressure a bit more. Eventually, the pressure curve goes the other way as you decrease case capacity.
You are likely nowhere near dangerous territory, but I have to ask: what do you hope to gain by running even more powder? Sierra 140 Game Kings aren't very stout bullets, and thus don't benefit from more velocity. You'd be better off to slow them down than to speed them up. Or, if what you've got so far shoots well, don't mess with it.
