arrow spine question

[jkyarcher]

I recently bought one of those spine test kits that include 4 different spine wood arrows to see which shot best with my recurve bow.

After cutting them same length and putting on same weight points I went and shot groups from various distances. I notice two arrows shot better than the others and checked the chart, one had the lightest spine of the kit and the other had the heaviest spine of the kit.

My question is why would the complete opposites shoot best and not the more similar ones?

I don't have a spine tester so I'm taking the manufacturer's wood that they are the spine it says it is.
 

[Pat B]

Shoot all the arrows with the cock feather in and see what happens. Both sides of the shafts might have different spine values. You normally want the stiffest side against the bow.