Jason; on the same armor plate test, without the IF's these same shaft setups fail first time, every time on both the frontal impact and the 45 degree impact. With just a parallel dowell (of the appropriaye length) they will stand up to the frontal impacts, but still won't hold up for a single 45 degree impact. The difference is night and day. Check out the shaft failure rates shown in the 2007 Update, part 2.
Andy, I haven't tried the IF's on Axis or Beman. Testing has been with Carbon Express, Gold Tip, Gold Tip UltraLite, etcetera .. the shafts with an ID of about 6mm.
As long as we're all 'wishing' I want a really well designed and constructed 250 and 300 grain GLUE_ON Broadhead and some STEEL inserts (in the same OAL's as the brass ones would be nice)!
Ed
Almost forgot; some of the nocks do occassionally pop off on the frontal impact hits, but I've have had no shaft cracks at the nock end.