Ackley Chambers
I knowingly bought a Rem 700 VS in .22-250 with a bad chamber just to punch out to the Ackley version. Sweetest crow buster I have ever owned with longest witnessed kill at 410 yards.
Consistently shot sub 1/2" groups with Remington Bbl on this rifle, even when fireforming cases. (Expect to lose about 1 in 15-20 cases during fireforming.
Full length resize new casings, and trim cases just enough to square up the shortest one of the lot you have. They are going to stretch during fireforming and you want enough material left so you don't end up with thin neck's.
Use a heavier flat base bullet with a long Ogive, and seat them out to engage rifling .002"-.003" for a crush fit. This will help ensure that your casings heads sits square against bolt face. Use a bulkier powder that will give you a full case..even better is a mildly compressed charge that still falls 10% below max load pressures for safety. And lastly.....keep a good chamber brush on the bench with you and clean the chamber frequently when Fireforming. Oil, unburnt powder kernels and powder residue in the chamber that will ruin a good case.
It never ceases to amaze me to put in a standard casing and pull the trigger, rack the bolt and have a different case eject into my hand. (Yeah, I am easily amused.)
A Local gunsmith (Springfield Mo) only charged me $40.00 to rechamber my rifle and another $15.00 to recrown it.
Get a professional to do the chambers for you......In the long run I think you will find the investment was worth it.
BTW.....The .25-06 is already an overbore cartridge and you probably won't see a real benefit to the Ackley treatment...if velocity is what you are after? What you will find is less case stretch with the minimum body taper, and positive indexing with the 40 degree shoulder.
As for the .338-06...sounds like a fun 1000 yard varminter to me.
Good Luck
