Have a Winchester Classic synthetic ( early 90's) that I placed a piece of plastic under each action screw and it solved this very issue I had. Now it will shoot first shot in in a half inch group any time I try it. I like to shoot on a windless day....only one shot and then next day fire that one shot and the two targets will be within half inch. What this did was allow me to run a dollar bill all way to the action....and before the bill would go only go about half way. There is a guy with a video on You Tube shows how to do this....remember my rifle when new came with some kind of plastic cement under the front screw and over time it had gone bad so I removed it and replace with a plastic shim cut out of a detergent bottle.....simple solution to my problem.
