I am thinking about building a couple of AI chambered rifles. I have build several standard cartridge rifles using short chambered, pre-threaded barrels. I have read somewhere that to ream an AI chamber you need to set the barrel back one thread before starting to ream so the new shoulder will completely clean up the old shoulder. Does this hold true for new, short chambered barrels? If my new barrel was say .050 short would the AI reamer clean up the standard shoulder without setting the barrel back one thread?

No.

Wally, maybe I am reading this wrong but if he has a short chambered blank by .050" and wants to make it into an Ackley, he can open it up to ackley by just reaming with the Ackley reamer. Right? Others?

I was thinking about this very thing earlier today. "As I understand it", the chamber is first reamed and headspace set by a standard headspace gage, then the bbl must be set back one turn in order to achive the crush fit. Doing it straightaway on a short chambered bbl "would" work if you had go, no-go gages calibrated for an AI chambering.

Is that correct???

Mr. Ackley designed his improved chambers to headspace .004 shorter than the standered chamber in rimless chamberings.In a rechamber,this means you have to set the barrel back in order to achieve this.You use an Ackley Go-guage, and your standard Go-gauge is used as the No Go-gauge.With a .050 short chamber there is no need to set anything back.Ream with your A.I. reamer and set the headspace with an Ackley Go-guage for that chamber and use your standared Go-guage as the No-Go guage.In doing this,you achieve the so-called "crushed fit".