[kraigwy]

I've shoot a heck of a lot of matches, with thin & heavy barrels, match and standard.

So as not to be repetitive, I'll just say I concur with Bart, he pretty much covered it.

Bart mentioned squaring the receiver with the treads. Regardless of what type of barrel you use, this is ONE OF the quickest ways to make a so so rifle accurate.

To see this, Brownell sells a Action Facing Mandrel. This is nothing more the a rod with a section in the middle that is treaded for what ever action you're using.

The action is slide onto the rod, and screwed on the threaded section. The rod is then put in a lathe between centers. Use a dial indicator to make sure the tail stock is lined up with the head stock.

Now take some layout ink or something else to paint the front of the action. Take a very light cut ( lets say .001) on the front of the action.

Chances are, you'll see bear metal on one side of the action face and on the other side you'll see the layout ink hasn't been touched.

I've re-barreled a heck of a lot of actions and believe me, few are square.

As Bart said, if the face of the action isn't square, its not gonna shoot the same if its hot as it did when its cold.

Talk about cold bore, the is the best way I know to get the cold bore shot the same as when its warm.