I got 4 Easton Gamegetter 2219s I am using to test some things out.  They each have 125 grain field points on them.

I have put duct tape (!) fletching on them, 3 vanes each.

My question is thus:  when I shoot, they're pretty straight, but it seems the tail end rotates around the point.  Imagine in a side view, you have the tip resting on the ground and the tail is tied off to a string.  If you gently swing the tail while leaving the tip on the ground you could imagine a cone shape being the spin.  It's nott huge, but it sure ain't parallax.  What could cause that and what can I do to keep it tighter?

I'm using a selfbow, shooting off my hand.  Each vane is approx 5 in L, 2 in H, either a basic triangle or half parabola

This is just a shot in the dark, but try cutting the tape like a feather on all of the vanes, or just the ones that touch the shelf.  This may allow them to lay down when they pass the shelf giving you cleaner flight.

That is why traditional archers use feathers on their arrows. 2219s are .337 spine which is pretty stiff. You don't say the draw weight of your bow, your draw, the length of the shafts. These are things we would need to know to help.

Your 2" high fletching is about 1 1/4" higher than feathers. It is undoubtedly striking the bow causing the issue you noted. There is nothing you can do with duct tape that will work...sorry.

Buy an inexpensive fletching jig and some feathers, some fletch tape and probably some properly spined arrows, and ask for some more help.

This is a great place to find answers. We are happy to help.

It may also be the pattern of the vanes. Do you have them on straight or are they helical?

Thanks for the inputs.

@30coupe, draw weight is about 45, not explicitly measured, but I've pulled that on a bow before.  It felt the same.

Length of shafts is 31 inches.  I draw just under 28.

I understand about getting a jig, but was just seeing if there was anything that could be done to improve besides getting one for now.  I would definitely agree with the vanes hitting the bow, though they feel as floppy as some older actual ones I have felt

@bigbadjon, I drew a straight line down the spine for my first one to line up, then the rest I eyeballed it oriented to the first.

Sounds like it may be more enjoyable all around to just invest in a jig and feathers.

I think the biggest issue you have is that those shafts are way too heavily spined for your setup.  At 31 inches, assuming you have a point weight of 125gr, those shafts have a dynamic spine of about 82#.  If your bow is truly 45#, you are way off.  You need a much lighter spined shaft.  If staying with aluminum, something like a 2016 or 1916 should be in the ballpark.

All accurate and good info above........I will add one thing: Arrows are not a good place to skimp or go on the cheap. Arrows are the most crucial part of your equipment!

All good advice, folks!

First, I think I need to detune the bow some more, as my daughter had trouble drawing it.  Once I get to where she is comfortable, then I will properly measure everything and just invest in the correct arrows.  She's not really interested in tradition equipment beyond the point where we can get her a bow from existing wood instead of investing in commercial bows.  She's beyond the usual gym class stuff