Muledeer offered this tip awhile back. For shims, use the plastic clips that come on bread bags .They have a hole in them that the screw can go thru and are about the same thickness as credit card.Take 3-4 to the range. I know a few guys that have shimmed their rifle and then never did anything else to it..
Whatever is done, make sure you fire 4-5 rounds thru your rifle BEFORE deciding if accuracy improved or got worse ,so you can settle the action in the stock. Then recheck you action screws
