Jim, I hope someone can help you. On the few barrels I have added to an action, only 2 fit perfectly. The rest I had my gunsmith fit them. I have no idea how he did it. One thing I do know for sure, is to NOT make any modifications to your existing action. If you do, then the original barrel and/or forearm may not fit. The only action modification I can think of that will not alter the original barrel fitting, would be to get another Locking Block for use only with the new barrel. Of course, swapping out the Locking Block every time you changed the barrel would be a real hassle. Please keep us posted on your progress. If any of your 220's have serial numbers, would you please share with me for my research, along with the exact model, i.e. 220A, etc.? Good luck on your quest. Garnett
Please be advised that my record of serial numbers have no names or addresses attached.