Such a thing as pistol harmonics?

From Wikipedia.....

Generally the harmonic effects are proportional to the square of the barrel length, and so are generally only of concern in long guns such as rifles but not handguns.

Is this to say that the phenomenon commonly referred to as harmonics is misunderstood at to what is actually going on, or just called something that it is not?
By that I mean is what people are referring to as harmonics actually occurring or is it another phenomena altogether?

IMHO, to a certain degree, especially in the case of handguns. I think many folks just lump many variables under the term of harmonics, and most of us understand. There are things such as secondary pressure from certain powders that affect barrel movement and accuracy. There's reasons why some guns prefer certain bullets/powders over others, some may have to do with how they affect barrel movement some don't. Is the movement all caused by the harmonic effect?


When you rest a gun on something you change the recoil dynamics. Have someone stand to the side and observe how much muzzle flip you get, then change your support position and see if that doesn't change as well. I took a slow-motion YouTube video of a 460 S&W with Magnaporting being fired and marked it with lines so I could see, between the flash appearing at the barrel/cylinder gap and appearing at the ports, how much muzzle rise there was. It's small but real and since it is happening before the bullet clears the muzzle, it raises POI. Putting the same gun on a bag, so it starts with the weight of the gun plus downward pressure from the weight of your hands, you should not only add friction to the rearward recoil but reduce how much flip you get before the bullet clears the muzzle because of that downward pre-loading, tending to lower POI. Conversely, a rest that lets you grip the gun lower on the frame will tend to raise POI because that increases the moment arm the flip pivots around. Consistency is everything in pistol accuracy.

I shoot a lot of .460. I have a long piped P.C. model which is scary accurate. Most of my shooting is off some kind of rest, i.e. bags, shooting stick, dedicated handgun rest, etc. Tried a Bi-Pod mounted to the front sling swivel mounts. What portion of the gun is rested makes a big difference in accuracy. Resting the barrel widens the group considerably over resting the front part of the frame. This grouping is not only vertical, but also horizontal, so the cause is not only difference in recoil rise/dynamics. One reason I removed the bi-pod.

Lot of theories out there, like anal orifices, everybody has one. Will a long piped hunting revolver have more barrel movement due to twist and whip than a snub nosed EDC? IMHO, Yep, just like that snubby probably will have more muzzle rise due to recoil. Does the less barrel dwell compensate for this? Somebody probably has a theory.

Odds are, if more folks shot their handguns at standard rifle shooting distances, one might see more influence in acuracy by those variables most folks call harmonics. If one shot their rifles only at a distance of 25 yards or less, how much concern, if any, would there be over barrel harmonics? Still, one only needs to re-read the quote from Wikipedia above to know the answer to the OPs question.
 
There are things such as secondary pressure from certain powders that affect barrel movement and accuracy. There's reasons why some guns prefer certain bullets/powders over others, some may have to do with how they affect barrel movement some don't. Is the movement all caused by the harmonic effect?
Totally agree with this--simply by virtue of the fact that you are more likely to not get near maximum burn efficiency in a pistol barrel than a rifle I suspect a lot of "funky" pressure wave and release dynamics are involved relative to projectile in bore vs after exit.
 
buck460XVR said:
Tried a Bi-Pod mounted to the front sling swivel mounts. What portion of the gun is rested makes a big difference in accuracy. Resting the barrel widens the group considerably over resting the front part of the frame. This grouping is not only vertical, but also horizontal, so the cause is not only difference in recoil rise/dynamics. One reason I removed the bi-pod.

I had that happen with my pre-Accustock Savage FP-10. The original thermoplastic stock was so flimsy that a bi-pod pushed the front of it right up against the barrel, changing the bending point. It actually wore a shiny spot into the bluing of the barrel pretty fast. I changed that stock, needless to say. But a bipod can be made to shoot.

One thing many have found helpful with rifles too light to be very rigid on bags is resting the magazine floor plate on the front bag to keep the influence on the stock away as completely as possible.
 
Back
Top