How long would one of them fishin' pole blanks last if you dropped it end first off the top of a 5 story building into the parking lot? And repeated the test time after time after time? You reckon the shock of impact will make the matrix will break down a mite and reduce the spine? How about giving them a rubdown with 600 grit sandpaper between drops. Think that will eventually change the spine? How about hooking one up and using it to tow a car out of the mud? You think that will pull the matrix apart a little? That' s what I' m talking about happening to the ICS type carbons. Flexing isn' t an issue, unless they' re really torqued around to nearly breaking point.

The problem with arrows is that not every arrow is shot into exactly the same place every shot. One will hit something a little harder than the one before it. One might wind up stuck in a tree or bouncing off a rock. Say you forget to lube your arrow and it gets stuck in the target. Takes you, two other guys and a strong mule to pull it out. You might shoot one arrow out of a dozen a hundred times and another only 30. Different accumulation of shock, stress and abrasion. The one shot more will eventually beome less stiff than the other one and they' ll start shooting to slightly different places.

Being carbon, I doubt they ever shot exactly the same to begin with, but that' s beside the point, and the beginning of another.

With my homemade spine tester, I' ve found that carbons are pretty much like wood arrows. And like fishin' poles. They have a side that spines stiffer than anywhere else around the shaft. With fishin' pole blanks, you run the line guides down the stiffest section of the rod for best strength and casting accuracy, right? With carbon arrows, put the cock feather on the strongest side for best consistency and accuracy. (At least, that' s my theory and what I' ve begun doing. Seems to help.)

But the carbons I' ve checked have been very inconsistent in spine. Even when comparing the stiffest section of each shaft to each other, and that' s even when they' re new. After they' ve been shot a good while....
You see how inconsistencies can develop within a dozen arrows after being shot awhile. When they start off inconsistent in the first place, and with the fletching stuck on without any regard for the stiffest section of each shaft, any wonder why those fliers start showing up?