IC: I hate to be a bucket of cold water,but me personally, I could never get very enthused about the whole AI thing. I say that knowing full well that a lot of very experienced guys on here love them.But really,if you want more velocity than a 7x57 gives, just rechamber to 280 Remington.Brass is common,and you don't have to fire form it.
Besides,what's wrong with the 7x57 the way it is,like Al Biesen indicated?