Talk to me about Barrel Harmonics? I'm trying to educate

Everytime the gun shoots that shit whips around. If it's consistent (no extra contact points or consistent contact points on barrel) then it's accurate.

To improve accuracy you must sing your barrel the appropriate tune.

18" barrels tend to like blues, anything shorter starts liking more hi-tempo stuff.

>>30753967
You see, each bullet leaves the barrel at a different time. Maybe it's .03 seconds but the next round is ever so slightly different in its charge so it takes .028 seconds. This means as the barrel waves around during the shot it will be in a ever so slightly different position at that time and alter the course of the bullet enough to affect your target. This is why bull barrela are good. They just whip less and have less deviation. This is also why consistency in loading ammo counts. If each bullet has the same barrel travel time, then each one will exit at the same point in the barrel "whip travel"

>>30753968
Can you elaborate more on this?

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>>30754049
>0.03 seconds

Where are you getting these numbers man?.

Have a read anon.

https://www.shootingsoftware.com/barrel.htm

Someone posted this video a bit ago. It's about airguns but pretty much everything here applies to firearms as well.

https://www.youtube.com/watch?v=VcME_2Efe_Q

>>30756129
His numbers are to illustrate a point in order to make the concept of barrel harmonics understandable to the common layman.

>>30754049
>Bullshit

>>30753942
Barrels are like most solids, when subjected to a shock, they will vibrate at their resonant frequency. The explosion in the chamber will cause a shock wave that travels in the barrels before the bullet exits (speed of sound in steel is ~20k FPS).

A solid when vibrating will have a waveform, with nodes and crests. Intuitively you'd think you want your muzzle to be at a node, or have your bullet exit the barrel when the muzzle is in its median position (average over a wavelength). That's actually not the case, because even though your muzzle will be centered, it will have its highest velocity and slope. Having the bullet exit the muzzle at a crest will reduce velocity and slope, and increase consistency (i.e.: accuracy). There is no "mathematical" way of solving this. Trial and error with different handloads, and/or use of different weight barrel tuners will help you find the most accurate match.

A thicker barrel (heavy barrel) or shorter barrel will have less amplitude, a long thin barrel will move quite a bit, you can play around with plastic tubes in a hardware store to verify this. A thicker barrel has a larger second moment of inertia, and thus will flex less, a shorter barrel will move have less amplitude (but higher fundamental frequency).

Vibration isn't a very complicated concept, but once you get into the math and solid mechanics, it becomes unattainable to most people (it's grad level stuff). For most shooters it comes down to trying different loads, muzzles, weights for each barrel.

>>30758338
> second moment of inertia
Sorry, I meant second moment of area (also known as "area moment of inertia" or incorrectly referred to as "moment of inertia").

>>30754358

I may make a mistake as it's been a while since I've been in college and used this stuff.

18" barrels like blues at around 70bpm, shorter barrels like progressively higher and higher tempo music. We in the trade have a term called the "Blues-Pop barrier", where the bpm of the music goes approaches 126 to 128 bpm, there's an age old argument on which one the barrier should end at. Around 16" is the Blues-Pop barrier in terms of barrel length.

Generally as you approach 10" you should be at near 240bpm tunes, handguns are especially hard to tune correctly as they've shorter barrels than that, which is why most handguns are less accurate than rifles. The barrel can tell if the tunes are shit. The longer the rifle barrel, the slower the tone needed, allowing for less skilled musicians to tune the barrels, making the gun more accurate.

It's a complicated subject, I can understand if you don't get it, we don't go to college to learn this stuff for no reason.

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It's similar to using a swing set in reverse. Basically shooting a round causes the barrel to rise and you naturally pull it down. At a certain point, your force pulling the barrel down overcomes the barrel rise. You then start pulling it down and the barrel has this damped oscillation. The goal is to then fire your next round when the harmonic motion evens out, allowing for another shot.
You can design a barrel in length and mass so that the motion can be reduced, so as to allow for a higher frequency of shots

>>30758767
>Basically shooting a round causes the barrel to rise and you naturally pull it down.

muscle force would have no impact on this at all. The bullet has completely left the barrel before you're aware that the gun has been fired.

>>30756129
see
>>30758007