Although I shoot GT Ultralite 500's and UL 22 series (all Pro shafts) I have to agree with These guys. The GT CAA is almost identical to ACC's in every respect except price. They are numbered a little different, but it's easy to cipher. A 3280 is the same as an ACC 3-28. They drop the dash and add a zero.

Getting back to the Ultralites---I like them well enough, but almost every time I have an issue with some all-carbon arrow I dig out the ACC's I've had for 10-12 years. They have never failed me when I want one of the most consistent arrows you can get within a reasonable price range. That being less than $150.