You may be a little underspined. The chart calls for a 340, but you are right on the borderline. I don't have any experience with the Axis, so I can't speak intelligently on those, in my mind I don't like the inserts. As far as broadheads go, my bow kicks arrows in the 290 region, and both Muzzy 100 gr 4 blade and 100 gr Magnus Stinger fly very well out of my setup.