Rechambering to Ackley

[Skunce]

I've chambered a few new barrels, but now I want to rechamber a factory 22-250 barrel to 22-250AI. I'm going to use this barrel for fire forming and short range varmint shooting and plan to buy another fast twist barrel blank for long range.
My question is how do you more experienced metal workers go about this. My thought was to set up through the headstock and dial the barrel in like I would a new blank, then bore the barrel deep enough to get the reamer pilot started in the bore. I've been using a Bald Eagle floating reamer holder, so I don't think it would be okay to try starting to reamer in the original chamber without the pilot for guidance.
I'm aware that I need to set the barrel back to clean up the old chamber. Do you have any other recomendations?

 

[watercam]

Just noticed that someone is selling dies for your project chamber on this forum.

 

[Preacher]

Just make sure the chamber is short enough so the new case has a bit of resistance when you close the bolt on a unfired case..... You are going to set it back anyways so the pilot should have no problem entering the bore...

 

[Skunce]

I was just going to set it back a couple of theads, it doesn't have enough shank to set it back the length of the case.

 

[Preacher]

A couple of threads removed may be OK, but it still needs to chamber a new 22/250 case a bit on the tight side to work as it should... The pilot should still fit the old chamber..... No real need to cut off the complete old chamber unless it's bad.. so have right at it...

 

[JJH]

Should be able to set back just one full turn of the barrel, still have stamps line up ect.. and have enough to rechamber if you are careful.

 

[Skunce]

I decided to set it back the length of the neck about .250". And I was able to time the barrel markings correctly. I discovered that a set of Lee collet dies I already have work fine for reloading the Ackley, so I just ordered a body die for resizing. The brass is fire forming very nicely and I've reached 220 Swift velocity easily. This weekend I hope to get to the range to test it on paper. Thanks for the input from all those who took time to respond.