Re: 6,5x55AI Reloading
What powders are Available to you???
I'm Certain that the data for the standard 6.5x55 is useable data for your purposes. The case capacity is similar to the increase of capacity for the .257 Roberts when improved to the Ackley version. I believe that a 10 % increase is correct for the volume increase.
I would use the max load data for the Powders that you have on hand and increase the charges to about 7% over the standard's max to keep it safe.
Do a search on Google, there are a lot of individuals out there who have asked this question, but I'd certainly like to know what powders that you guys have available to you.