I shoot an easton axis arrow and I think I might have the wrong shaft; it is confusing because I do not know if my cam is a hard or medium cam.

I shoot a Hoyt Powertec
68 lbs
30 inch draw
with a 28 inch arrow
100 grain heads

Currently I am shooting 340's but there seems to be a quite a bit of wobble in the arrow. Should I be shooting 400's instead? Does anyone know if my cam is hard or medium?

Any help would be great - thanks!