I spent a big chunk of the day bare-shaft tuning arrows for my new bow. (
WARNING: Nerd-level archery treatise alert)
What you do is fiddle with various parameters, especially arrow length, until they are flying perfectly.
Here's how it works. Wooden arrows aren't rigid; they are surprisingly bendy. So, when one shoots a bow that doesn't have a center-cut arrow rest, the arrows have to flex around the handle upon release. If the arrow shaft is too bendy, it will whip around the handle too far and hit off to one side; too stiff, and it won't bend around the handle enough, and hit off to the other side. Longer arrows are more flexible than shorter ones (think how you can bend a yard stick further than a ruler before it breaks). So with patience, one can start with an arrow that is deliberately cut too long, then shorten it gradually until the flexibility perfectly matches the power of the bow and the shape of the handle.
(Look up "slow motion archer's paradox" on YouTube if you'd like to entirely geek out about this with me. I find it interesting. You may not)
Now I have arrows hitting the bullseye at 10 yards, with no feathers. That's kind of satisfying. Tomorrow I'll cut all my arrows to that same, magical length, color and fletch them, and Bob's your uncle.
Once the arrows are tuned that well, the feathers become just a backup system, keeping the arrow on course in case of a bad release, all to common at my skill level. They also impart a bit of spin to the shaft, which can help it stay on course for longer shots.
And now, you know more about arrow tuning than you could possibly care about.
