[Andyakashrek]

I have a pair of TXS's #38 and a set of KAP challenger carbons #36, both 68", so according to Easton they should use the same arrow spine. I use 2012 X7's and 3-04 ACC's at 28", T5 IIRC.
However the challengers shoot far better than the Borders outside. At 60 yds unless release is very good the arrows wont group while the challengers will, all 9's and 7's.
So after a paticularly bad round at Cleve, a Judge commented on how the arrows were leaving the bow sideways, I started thinking. The Borders are far more aggressively recurved and much faster, is it possible that I am underspined? Clearance, nock height and centreshot are all OK and I can bareshaft smack in the group at 30 Yds. The grouping and scores are good till 50 yds and then open up drastically.
So assuming you have spined your Borders and have no issues how does your choice compare to Eastons charts?
Brilliant limbs just need the correct arrows I think.

edit;
the ACC's have 70grn piles if I changed them to 50grn piles would it stiffen them 1 to 2 sizes?