here are two things to look at, and these are from past experience.
1. if you happen to be using the factory Ruger rings, swap them out for a convention base and rings! A couple thousandths slop here will give you almost two inches at 100 yards. Also if your rings are solidly anchored in the receiver, then lap them. As things begin to heat up they will move all over the place.
2. Now this is tricky, but pull the barreled action out of the stock and inspect the area around the angled screw. This can make or break you here. It doesn't take a lot to make things go bad here. You might try adding a .003" or a .005" plastic shim there to see if it helps. If it makes a difference, then you need to lightly skim bed that area again (that's what I had to do with one rifle). I suspect that everybody has their own method of tightening these screws. I like to do the front and back ones down to about 30 inch pounds, then bring the center one down to the same. After that, I bring the other two down to 40 inch pounds, and then bring the center one down to the same or slightly under or over in in tension (I find the rifle vary a bit). The torque wrench you use has a lot to do with the end results. Forget the break over ones, and find one with a dial. Look over each screw under a strong light. Look at the first two threads at the end to see if they are shiny or even discolored. If they are, you might need to either run a tap into the holes for a clean up. You also might need to grind a thread off the tip of the screw itself.
Now when you have the barreled action out of the stock, look for some warpage in the forend. Look to see if the receiver area is contacting the bolt handle or even the trigger. Have seen this more than once in several rifles. Also make sure you have at least .06" clearance around the barrel everywhere, and .093" would be better.
Eighty percent of the end users of a torque wrench use them wrong! You see this everywhere from race car guys to folks like me and you. Few people actually look at the bolts and nuts they are tightening, and trust me a nicked up screw at the low specs will give you a false reading. With a dial type wrench you'll often see things start to go bad. I like to coat the threads very lightly with Never Seize With Nickel (do not use Loctite Anti Seize!!). The can calls for you to reduce the torque spec by 50%, but 35 inch pounds will do nicely, and not over 40 inch pounds. (that spec is usually for bigger screws). When tightening these screws, turn the wrench slowly while holding it steady at both ends. When you see a guy just cranking the wrench away like he was in hurry the specs will be off a bit. Lastly; no matter how accurately you torque the screws, the area they seat against must be good an perpendicular to the thread. If that area is rough, you never get a good spec.
gary
