Arrow length and impact

[the rifleman]

i shoot full length 31" carbon arrows 600 spine w 200 grs up front out of my 42 pound Whip.  These arrows tune very well but come in at 495 grs.  I have been playing w aluminums in 1716 w 125 up front.  Cut at 28.5 they bareshaft weak and fly noticeably to the left at 30 yds ( I shoot lefty).  When I fletch them they group very well but about 5 inches to the right of the carbons.  Not sure I would call my style gapping, but I am aware of the arrow in my peripheral.  I am thinking that the longer arrow makes me adjust my aim further to the left and when I switch to shorter arrow the "sight picture" is different enough to cause my groups to go to the right.  I am pretty sure that if I make the switch to a shorter arrow that I will adapt, but am I right in thinking the visual perception of short versus long is moving my shot to the right?

[pdk25]

[pdk25]

http://www.ptacnik.net/Bogensport/Tuning/Easton%20-%20Complete%20Tuning%20Guide.pdf

[old_goat2]

Arrow length shouldn't effect left and right other than if the left and right is a result of improper spine. Different length can very well effect your up and down assuming they are both tuned because it will change your point on reference

[the rifleman]

Left impacts are weak for a lefty.  But not talking tuning really just aiming/ perception.  In other words if both arrows are in tune could length cause right or left impacts?

I would think that a longer or shorter shaft would shift you up and down, but not sideways! You mind is used to putting that tip in a certain place. if you cange the length and still put the tip  in the same place, it will change your point of impact up and down.

Bisch

[Shadowhnter]

I think it would effect your impact both up/down and side/side if your mind and bowarm hasnt made the adjustment yet.. In otherwords i think you would see it move low and left for a shorter arrow and being a lefty, if your bowhand was in the same position as it was for a longer arrow. With you using a mix of instinct and point gap, i think thats possible if you rely more on instinct then you might realize.

Id wonder if It also will make a difference if you use a canted bow, or straight.

[Rough Run]

I shoot aluminum.  Assuming a 28" draw, out of a 42# bow, I think you may get more similar results from an 1816 w/125gr (& maybe even 145gr) points left at your usual 31".  That would give you a total arrow weight around 425gr (minus fletching and nock).  You could slowly trim them down, a little at a time, if you just wanted to shoot shorter arrows.

[Bladepeek]

I think if your aiming eye is not exactly over the arrow and your brain is applying an automatic side correction, a different arrow length would change the left/right impact until the brain "recomputes".

Howard Hill said that his arrows flew up and left of his sight line.  I try, I said, try, to reference to where my arrow is on my finger to avoid that perception difference.   I would bet you may have a little argument going on in your subconscious and are splitting the difference.

[pdk25]

[pdk25]

[pdk25]

[Bowwild]

Rifleman,
The spine issues above might be the problem.  But, your perception that "sight picture" is different from long to short or vice versa could also be the case, especially if your alignment with the bowstring, arrow point, and target reference aren't in line.  

I for instance sometimes neglect to get the bowstring directly in front of my eye (should happen without thinking about it).  I should either be looking through the string or beside it, the same every shot.

If your view is out of alignment and the arrow length is significantly different, your windage could change.

So, like you, I'm not ready to automatically going to blame the entire windage difference on dynamic spine changes. Of course you can easily prove or disprove this by adjusting your eye alignment with the bowstring from shot to shot.

[The Whittler]

Right hand shooting to the right is weak. Left hand shooting to the left is weak.

[Stumpkiller]

I agree that it's more likely a spine issue than a length issue.  Adjust your brace height to see if that corrects it with your arrow of choice.

[pdk25]

It seems I misread the Easton site.  Sometimes it is better to keep your pie-hole shut unless you are certain.  Sorry about that.