I've got a bit of a problem. I think my arrows are a touch over-spined and may be the cause.  What's your opinion? Do you think the cause is the arrow, tuning, or shooting form?
 It's a 55# Tomahawk...has a "grooved" shape for the rest....not just an angled shelf. The arrow is showing contact (a lot!) on the outside of this groove. I understand the archers paradox bending of the arrow but this grooved shelf design seems to inhibit the natural flex and somehow it's getting over the lip and hitting on the outside anyway. And yes....I don't get good clean flight!

I had a similar problem on a Bear Patriot longbow that I owned.  The shelf is also slightly grooved.  I raised the nock point slightly and went to a weaker spined arrow.  My arrow flight improved immediately.  Hope this helps.

Yep.  I'd suggest raising the nock point as well.  And/or turn the cock feather in if you're shooting three fletch.  Only do one at a time, though.  Try the cock feather in first.  If that doesn't work, raise the nock point.  Good luck.

I had this same problem on my Ancient Spirits recurve. Shooting cock-feather in solved the problem.

ben