#1 A good cleaning with known top quality bore solvents with a guide and good cleaning rod. I have used shooters choice for years and now find I like bore tech as well or better. #2 Get a inch/pound torque driver for action screws and scope mounting. A good cleaning till blue green no longer stains patches and torque action screws to Browning recommendation and shoot. After that then if groups are not good look at trying different scope. No point going to scope till after a fouled bore and properly adjusted action screws are eliminated as the problem.