I've used Beman carbon arrows for a long time. I finally exhausted my supply of shafts and glue-on components, so I bought some Beman ICS camo hunter arrows.
I was bummed out a bit when I saw that I was getting 1/2 the target penetration I was accustomed to with the old Bemans.
Gathered a little data. Both arrows Finished length 30.5", 4" plastic fletch, 100gr tip, spine is 75/85 for old carbon and ICS 300 for new.
Old-style Beman Carbon:
0.241" shaft diameter
Beman ICS Camo Hunter:
0.305" shaft diameter
So although the speed went down by 5.3%, the momentum increased by 8.7%, KE increased by 3%, yet the penetration decreased significantly. Decrease in penetration is due to shaft diameter increase and perhaps the camo finish. I don't know why Beman went to fat shafts, but they traded off penetration.
Summary: skinny carbons rule![/]