Lapping the scope base will only ensure a properly mounted scope, and will not really effect the potential accuracy of the rifle. But there are a whole crapload of things you can do to really make your rifle sing. You can start out by having your 'smith squre up the action and smooth out the bolt. Make sure the bolt face is perfectly concentric and headspace is correct, though this should not be a problem. Then you have to spend the time to either find a good factory load or custom roll one that does the best with your rifle, utilizing a bullet weight that coincides wiith the rate of twist in your rifle. I assume the rate of twist is probably one turn in about twelve inches, so it will do well with match bullets of 168-175 grains. Federal Gold Medal match would be a good place to start (and probably finish
) You'd be surprised at the accuracy differences that can occur between two different loads. And then you can have the action pillar bedded to the stock, which will make it stiffer and thereby increase potential accuracy. Get a trigger job done to ensure a smooth pull, which will enhance your accuracy. Make sure your scope is properly and securely mounted in a good set of rings (not $10 Wal-Mart specials). An dfinally, you can invest in a match grade barrel, from somewhere like Lilja or Wilson. But it probably wont need a whole new barrel just yet. Hope this helped.
Jake
Jake