Thread: Light tuna gun
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Old 05-15-2012, 02:42 AM   #13
spearq8
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Join Date: May 2009
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Re: Light tuna gun

I did a lot of pool testing last year to test how shaft whip affects accuracy. What was interesting was that it happened very predictably and could be induced by changing a few parameters. In some instances I was able to cause shaft whip by simply doubling up the bands on the back notch on a shaft that was right on the edge. So if you are on the edge of a shaft whip profile, simply reducing the effective length of the shaft can prevent shaft whip. Also there was one instance where an identical length shaft and identical thickness (both 7.1mm) where I had one whip and the other was stable. It turned out that the whippy shaft was a batch that was not heat treated properly (according to the supplier). So even a change in the metallurgic composition of the shaft can change the shaft whip profile. One thing is absolutely certain is that you do not want a shaft that whips as it dramatically hurts accuracy and the shaft impacts the target at strange angles.

My advice would be to avoid any shaft whip inhibitor if possible but if you really need it have it only at the first 20 or 30cm. I found absolutely no difference in accuracy in an enclosed track and non enclosed track ... so long that there was no shaft whip on the open track gun. Up to 160cm length @ 7.1mm using a Riffe shaft you will not get shaft whip with 3 x 15mm stiff bands. If I was going to do a new gun today, I would put the inhibitor all the way to the back of the trigger and have it extend to the furthest fin with a "V" shape to allow easier shaft insertion. This will avoid any chance of having the fins smack into the inhibitor and most likely your effective shaft length would be 20cm or 30cm less ... which would change your shaft to being effectively around 130cm. I tried very hard to induce shaft whip on my Beuchat Carbon 95 using a 135cm shaft with a 6.75mm shaft ... but even with 2 x 20mm stiff bands I couldn't do it. The recoil was hellish but the shaft impact on target was flat. So a small change in shaft length goes a long way.
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