You might consider talking to the people at Ruger. A tech, not the phone clerk. Find out if the screw "should" be removable, and if its not meant to be taken out, don't.
If its something that is meant to be periodically removed (like removing the stock) if its too stuck to come out with normal means, it might be something the factory needs to fix.
I'd at least talk to the tech guys at Ruger, first.
Consider a worst case situation, the screw is in so tight (for whatever reason) that you twist the head off trying to get it out. If that happens, you might need to send it to Ruger, anyway...