What you ask is a very good question I hope somene can answer. It is the more important factor of the three--spine consistency, straightness, and weight tolerance, pretty much in that order. Unfortunately I have e-mailed some of the companies that make AC arrows with this question and so far have pretty much gotten the run around. I guess you have to own your own spine tester to get the right answer. Then all you need to do is buy a lot of arrows and test them. Far beyond the means of most of us.

You' re right about the ACC' s. Easton does give spine tolerance for these. They are small in diameter, too. I shoot a hard helical and just put a drop away rest on to correct the problem. Really I always shot a Star Hunter and didn' t have a problem as I shoot feathers, but the Muzzy ZE took care of anything that was happening.