bare shaft tuning question

[Fishers]

I've been reading this (http://bowmaker.net/tuning.htm) to see if I can tune my 56-lb. recurve to shoot 2216s well. With a 125-gr. point the bare shafts hit 8-10" right (weak spine) of the fletched shafts at 8 yards. When I went to a 100-gr. point they hit right on, even back to 12 yds. Is there any rule for what change in shaft length will increase stiffness by the same amount as a 25-gr. reduction in point weight? Or should I just cut off 1/2" or so at a time & stop when it's right? I want to stay with 125-gr. points.

[turkeyslayer]

I would only cut off a 1/4" at a time,till i got them right,jmo.

[Encino Man]

Originally posted by turkeyslayer:
I would only cut off a 1/4" at a time,till i got them right,jmo.

I would agree. There are general rules but the best method is to shorten a 1/4" at a time until you are mildly weak. Then by the time you fletch them, they sould be right on.

[Bowmania]

This is a quote from David Soza in TradArchers' World Mag.  Outstanding publication.  "I also tested a number of other tuning factors.  Adding 100 grains of weight to the front of the .500 shafts made them hit six inches to the weak side.  That is the same  effect as removing two inchers of shaft lenght.  So, one can conclude that one inch of shaft lenght or 50 grains of poingt weight will move the bare shaft about three inches at 20 yards.  Turning down my bow two pounds brought the bare shafts back three inches to the strong side, so two pounds of bow weight appears to be the equivalent 50 grains of point weight or the one inch of shaft length with my set-up."  Must have been shooting an ILF.

Can you assume that a 2216 which is stiffer than a carbon .500 would have the same characteristics?  I don't know.  But gives you something to play with.

Bowmania

[bshunter]

very interesting info, I would like to see more tech info here, thanks.

[Bowmania]

Fishers, I used to shoot 2216's out of 68lbs at 30 inches with a 125 gr head.  Arrows were swedged (no inserts).  Looking at averages your way to stiff.

We'd sure like your draw length cutting will probably make it worse.

Bowmania

[Paul WA]

I think 2016 would be perfect for that set up...PR

[craig1955]

I agree with Bowmania, 2216 seems too stiff unless you have a really long draw.

[Steve O]

That's what I thought when I saw 2216 and 56#...WAY to stiff!  Are you using a 300g head?

[Jeremy]

Fishers,

Dropping 25 gr in point weight in no way should bring the arrows over 8-10", especially not at 8 yards.  I suspect, like others, that you're way overspined and bouncing off the strikeplate, giving you a false weak indication.