If looking for an internal carbon ferrule for SkyShark P400s, or Victory V6 shafts, please note that the Easton Carbon Injexion 330 arrow shafts are .244" OD (outside diameter). The P400s and Victories are .245" ID (inside diameter). It is a snug, but not tight fit. Unfortunately, about 6" of the Easton shaft has a glued-on wrap.
The rest, though, is usable for ferrules. It is a strong, 10.1 grain per inch tube, that should have good break strength. There is an unglued wrap at the nock end that can be stripped off and cleaned with alcohol. A dozen puchased from bowhuntingoutlet.com unfletched will yield about 96 ferrules of 3" length each at a cost about the same as the $1.25 apiece that FibraPlex charges for .240" OD ferrules that are too loose for the P400s and V6s, and not as strong.
Hope this is of interest to any other carbon tent pole makers out there. If so, be sure to get the 330s, as the other Injexion shafts are different diameters, and are not all carbon.