Guess we're talking about carbons. Personally I shoot Gold Tip Pro Series, but here's my experience. If carbon arrows are not stright it's usually at either or both ends. That's why I cut about 1 1/2" from the nock end and the rest from the point end. I end up with about a 27" arrow (that's for me). Assume starting with an arrow that is advertised at .005" I can end up with a shaft that is about .003".

If I start out with a .003" shaft then I end up with most being about .001". You get the picture?

However, to achieve these results I NEVER buy finished arrows because they are not cut from both ends. Besides, I've made up my own arrows for 30 years now.

Now, can I tell the difference between, say, .006" and .001"? You bet. I can tell the difference between .006" and .003". But I can't tell the difference between .003" and .001". Each person is going to be different in that respect.

Some other issues that come into play is that many times it's not just the straightness that is better. More expensive arrows (better grades) usually have tighter tolerances in weight and spine deviation, too. And some may disagree, but the spine deviation is the more important of the three qualities being discussed here.

Now, being a staff shooter I get the cream of the crop, but even before that, when I shot aluminums I shot the best available. Were I buying carbon arrows I would most likely go middle of the road and buy shafts with a .003" tolerance----Gold Tip Ultralites just in case you're curious. For hunting I'd use the XT's.

Hope this helps.