The barrel whip article only shows impacts on a vertical plane. Even if one round was to have higher trajectory than the rest, it would still follow its horizontal deflection.
Doc,
Please read read the article I posted as well as the posting of Mr Litz regarding "Positive Compensation". I think we're all in agreement it manifests in the vertical plane only. But the MV differences being compensated for by barrel whip is what I think you're looking for.
Chris.
I'm not sure that the article in post #90 makes the assumption that the ideal barrel can be positively compensated and indexed to resonate in the vertical plane alone? The article avoids making a definitive statement by introducing a casual observation instead:
Shooters who have attempted to bore sight rifles... has probably found that the point of impact of the bullet in the vertical plane, when the rifle was first fired, was much farther off from the bore sighting than it was in the horizontal plane
Barrel vibration is predominantly in the vertical plane by design (e.g. stock pressure points) or by gravity, but this does not exclude it from 3D vibration in the horizontal plane to some degree.
I've found the effort that golf club fitters go to analyse shaft orientation relatively enlightening when it comes to better understanding light barrel whip, given my ability to learn and resources I have available. Certainly much easier to observe the harmonics. Notice the reductions achieved, but never actual zero orientation.
Example
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Also, if we accept variable muzzle velocity, then Njord will also see fit to play his part in changing the point of impact, predominantly in the horizontal. BC and else being equal of course.
I would argue that the reality is a barrel (horizontal) vibrates 3-dimensionally, but that gravity has a significant effect on increasing the amplitude of the vibrations through the vertical plane, regardless of the natural vibration pattern of the barrel (e.g. pointed vertically). Vertical frequencies are also more likely to be more significant for long thin barrels, than short stiff barrels.
Practically whether we can measure the array of frequencies in 3-D and correlate them to any horizontal dispersion is only useful if we can measure the results on the target. The same applies to the effects of wind with changing velocities between shots for a perfectly tuned positively compensating barrel. I would suggest that for the average fullbore rifle with a positively compensating barrel and current target sizes, the horizontal dispersion would not be a significant consideration. In F-Open it might raise an eyebrow, but probably not until these shooters explore longer, lighter profile barrels in the search for more efficient velocity gains than powder/case size alone.
Can't wait for some LRH discussion on barrel indexing vs. barrel tuners vs. barrel dampeners vs. barrel blocks vs. muzzle breaks vs. front sight tunnels vs. bloop tubes vs. silencers...the 22LR BR shooters might even start subscribing
