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Old 3rd October 2013, 01:57 PM
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sven sven is offline
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Member of: FT Schalkhaar / SSV Ons Genoegen
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Originally Posted by kieran turner View Post
The barrel harmonics theory relates to recoil, now seen as most pcp's are considered recoiless in a conventional sense, do you still think that this theory would still stand with pcp's air rifles due to the extremely reduced affects of recoil.

By the way thank you for posting that, very interesting read.
My 12 fpe PCP air rifles are certainly not recoiless. I was amazed about the amount of movement when I once shot my Walther Dominator lying on its own on a table, not held by a shooter, only lying on the horizontal part of the fore end of the stock just before the trigger. I was trying to shoot it "free recoil" as benchrest shooters call it and only touched the trigger. Try that for yourself once and you'll never use the word recoiless again. Air strippers reduce this effect but not completely. When a shooter holds the rifle al lot of the movement is absorbed by the shooter holding the rifle so it looks like not much is happening.

Would the positive compensation theory still stand for an PCP? Could be.
The recoil in a PCP is much less than in a .22LR because of lower projectile energy and lower jet effect of the exiting gasses. But then again the striker in an PCP rifle is much heavier than a firing pin in an .22LR. The barrel in a PCP is also much thinner than in a .22LR matchrifle as used by Kolbe. It might be that there are barrel vibrations that are large enough to be compensated when the ideal tune is found by batch selection of pellets.
I have heard and read anecdotal evidence that a PCP shoots smaller groups when shot from the shoulder than when shot from a clamp or vise with the same pellets. This would support the idea that a PCP barrel does have its harmonics and that the positive compensation theory from Kolbe would also be valid for PCP's.
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