I have to agree with Matt on the cam sync.
When I got mine one cam was out only atwist of the cable but enough to effect the speed.
Once we got them in sync the speed went way up and i am not talking 5fps I am talking 20fps.

Mine was shooting with a 345gr arrow at 288 with cats whiskers peep and loop and a 385gr arrow at 275fps.
I have since added the magnocks and am getting 295fps from a 317gr arrow with the added magnock reciever on the string.