SA, before I walk away from this brick wall to take care of the bumps it's left on my head... You've been constantly returning to the issue of arrow spine and, I admit, I'm a bit hurt. Surely you don't think I have overlooked something THAT basic, do you? It's part of the tuning procedure.

Sometimes just changing the draw weight of the bow by 1/4 turn on each limb bolt can match the bow better to the arrow's spine and have dramatic effect on group size. As can making the tiniest changes in cam timing/rotation/synchronization. Or tiller. Even cleaning or replacing the cable slide can have a measurable effect. It's not always nock point and centershot you need to take care of.

Hmmm.... As I was typing this, a little light bulb flashed over my head. It may be with carbon arrows - and the spine inconsistencies that I and others have documented on the forums - that it's not possible to fine tune group sizes like I'm describing. Might have some bearing on why you think this is all poppylarky. [&:]