Standard chamber? As far a I know there is no such thing in 260 AI. If memory serves correctly, Ackley never did a "260 AI". It's easier to say than 6.5mm-08 A-Square, Improved, 40 degree shoulder. That's why everybody calls it a 260AI. Not to quibble but it sounds like Jim just has two different reamers that he uses. Nothing wrong with that. There are so many different ones out there though.
If you want to use your rifle as a repeater with the 260AI you'd be better off going with the shorter, .098, freebore. I don't think you'll be able to get close to the lands and be under mag. length with the .160 freebore. Fore example, if I'm doing my math right, a .160 freebore would put a Berger 140gr. VLD at the lands with an OAL of about 2.972. With a .098 freebore you'll be at the lands at 2.882. (or there abouts)
If you want to maximize the case capacity and shoot the heavies you'll have to single load. If you want to shoot the 140gr. class bullets from the magazine you'll be giving up some powder capacity do to the bullet base protruding into the case.
Something else to consider is your bullet choice as it relates to OAL. A 140gr. Nossler Accubond will seat .184 shorter OAL to the lands than a 140gr. Berger BT Target LR. The difference in the length of those two bullets is .013. It's the shape of the nose, or ogive, that makes the difference.
You're going to have to compromise somewhere.
I don't have a Criterion barrel but I do shoot a "260AI" of my own spec.
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