,,,,, I can tell you from test i did last September, that carbon will fly straighter then the aluminum. I have two Barnett Quad 300's. I set up form a bench and measured off 10 yards to be very sure of the distance. I was shooting from a bench. The Aluminum flew higher. The carbons flew straighter. Reference the 2nd picture below.

The 1st picture is a 10 yards shot from one of my treestands. The decoy is 10 yards out from the base of the tree and I am 18 feet up in the stand. The aluminum bolts are in the ground on the other side of the decoy. Those are carbon bolts in the decoy.