If you have a very tight action, why would you want to change it? Bolt actions are supposed to be tight. Is it tough to extract? the bolt handle hard to lift? Your locking lugs might have too many tool marks on them or you are shooting loads too hot for your rifle. Your best bet is to leave it alone, or put a little lube on it, even a little powdered graphite on the locking lugs. If that' s not satisfactory enough, run the bolt back and forth a thousand times while watching TV or open and close it as many times to slick it up a little and break it in. I wouldn' t recommend lapping the locking lugs unless you are replacing the barrel because it will increase the headspace slightly, and you only have few thousanths of an inch of change before your rifle is unsafe to shoot. The best way to lap them is to do it with the barrel off anyway.