x 2 on the FMJs...but I think mine are more around 11.3 gpi, id have to check though. Amazing durability, best of both worlds as gr8 said. Straightness of durability and strength of carbon with the reliability of aluminum. Thin diameter and HIT inserts as well. Ill shoot these as long as I continue with the semi heavy arrow theme. I have 12, and suspect they will last me quite some time before the need for upgrade. I dont shoot groups, so the only thing that can ruin them now is basically non pass thru shots at game, but killing a deer is worth several arrows to me. lol