I had a similar problem with Savage I put together for a friend. Though our problem was horizontal stringing. I suspected the bedding might be the problem ( My bedding, picture perfect Devcon on factory pillars) I cut 2 small squares of credit card plastic and placed them between the front action screw & magazine and the 2nd piece between the rear action screw & magazine. This lifted the action out of the bedding slightly so only contact was Lug & the two pieces of plastic. The rifle immediately went to shooting bug holes. So I think there's something to be said for FOXX's input. Haven't been able to re-bed yet as my friend won't turn loose of the rifle long enough :)