I think you may have bigger issues than just making the base fit. Have you shot the rifle yet? How smoothly does the bolt cycle?

Without trying to straighten the action, I wonder if some Burris Sig Zee rings mounted in a 2pc fashion would allow you to straighten the scope to the bore enough to get it straight.

However with the action twisted like that, I am betting that it doesn't sit in the stock properly at all, and when the bolt is engaged it may not be placing the lugs properly on action's bolt ramps, and for that matter the barrel could be sitting crooked to the rest of the action.

Based off of the picture there is a heck of a slant going on there and that is going to transpose in the scope, without getting the action straightened I think you are going to end up chasing your tail with issues. Sometimes they can be straightened and sometimes not.

If you want shoot me a PM and we can chat about it in a little greater detail if you decide to go that way. I'll help with info however I can.