Originally Posted by sven
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.
I know there is no such thing as recoiless with pcp's it is a different sort of recoil to say that of a centre fire etc.
I myself shoot an LG300 and that is some what flippy in comparison to other pcp's,with regards to shooting tighter groups from the shoulder instead of from a vice I myself have experienced this with this very rifle.