Why do specific arrows rise?

[AdamW]

Greetings all!

I have recently started making my own medieval style arrows and I am having trouble with a couple of my arrows that consistently rise when shot. None of my shafts are perfectly straight I there is a degree of bend in ever poplar shaft that I've ordered. I can't find any noticeable difference in crafting method as I make the all the same way. Is there anything I should be specifically looking for on the arrow that would give it too much lift?

[bowtarist]

If I'm shooting good droups and have an arrow going astray regularly, I mark that arrow, sharpie, and make sure it is the same arrow each time and not me.  Are you canting your bow?  Possibly an over spined arrow will fly high or right, for a right hand shooter.  Possibly flying high if you are dong a heavy cant.  Good luck, dpgratz

[AdamW]

What does "canting your bow" mean? 

I already marked the arrow so I know exactly which one is giving me problems. What about structural problems on the arrow itself? Like if the cock fletch is too long the arrow will always behave in a certain manner... Any rules like that?

[M-P]

If it's always the same arrow,  would guess that the shaft is either warped, or there's some weak area in the shaft that causes it to flex different than the others.   
Canting the bow means shooting with the bow tipped to one side.   Olympic style archers ( and compounders) shoot with the bow perfectly vertical. Many trad shooters tip the top limb to the right ( right handed archers.)     Ron

[mullet]

Did you orient your grain with your nock? If not try turning your arrow ove and shoting with the nock feather towards the bow.

 You should line your string on your nock in your arrow perpendicular to the grain. Like a Plus sign.

[AdamW]

There is a very specific method to constructing medieval arrows that Richard Head provides in order that other may duplicate his process.  Many of the steps are on youtube videos as well as instructions that come with arrow kits.

Rotating the arrow won't work as the "cock" feather will slide against the bow pushing shots to the left (right handed archer).  I noticed that one of the fletches was about 5mm longer(taller) than the rest so I trimmed it down but haven't shot it yet.

I will update you all this weekend after I've finished a few more arrows and had a chance to shoot.  Thanks for your help!

[crooketarrow]

  All arrows come off the bow at the same place. I'd say the arrows have about the same bend in them around the same place. Alowing them to come off the bow the same way.