I had chokes opened by the gunsmith at the local gandermountain. He used a reamer piloted from the muzzle. Cost me $130. I recently had chokes opened by Mike Orlen. It cost me less than $100 including shipping both ways. He pilots from chamber and bore. This is what this guy does, day in and day out. Let me tell you, there is a dramatic difference in quality. In my mind, it is a no brainer. For less than $100 you can ship those barrels from MT to MA and get it done right.