I hand reamed a 270 to Ackley with a reamer from Elk Ridge, the story started after I shot it and found it very inaccurate, learned the barrel wasn't fitted properly, and the barrel face was irregular, so I trued it up and got it fitted well, but the chamber was too shallow to load factory ammo, so it needed to be recut, instead of running a regular 270 reamer into it, I decided to rent an Ackley reamer instead, this was on a fluted bull barrel that is no longer made, so sending it to H&R wasn't an option even tho it was a factory rifle. It shot factory ammo just fine after the rechamber, but it wasn't accurate, after slugging the bore, learned it was .2795" instead of .277", so I shoot handloaded .284" bullet in it which shoot 1" so far.
My point is, you may be able to rechamber it by hand, or just have a smith do it, but if the barrel face isn't shortened first, you won't be able to shoot factory loads to fire form, you'll have to seat bullets long into the lands or create a false shoulder to headspace on, or use one of the bulletless methods of fire forming. Normally when a barrel is Ackleyized, the barrel is turned into the receiver a turn or two, then the chamber is recut, that can't be done on a fixed barrel, so you either end up with an improved-improved chamber that is slightly longer to the shoulder and will have excess headspace until loads are fire formed, or you must remove metal from the chamber face which will require the barrel to be shimmed to be fitted again which is what I did.
Tim
