Either will be fine for deer, targets, and moose.
What is your ideal arrow setup? Light and fast? Heavy and slow? Somewhere in between?
Besides component systems, the biggest real difference between these two shafts for hunting purposes is weight. The Axis will be about 1 GPI heavier than the 6.5 Matrix (or an equivalent good quality .246 arrow).
For similar setups, you can generally expect 10 fps faster speeds out of the bow from a 6.5mm arrow compared to the heavier Axis. What doesn't get talked about much is that downrange the heavier Axis will be retain speed an energy better and be about equal at 60 with more retained energy.
So, if all my shots were 20-30 yards from a tree stand, I would shoot the light, fast 6.5mm since it will drop less over my typical shot distance than the Axis. But, if I was going to shoot elk or moose at any distance, then the heavier Axis carries energy a little more efficiently better and the difference in drop starts to be negligible at distance. Also, heavier arrow will be a touch quieter.
Of course, end of day shoot whichever tunes and shoots best for you!