Measuring resonance on the barrel

[delooper]

Does anyone make a light-weight high-frequency motion sensor that would be suitable to mount on a barrel, so that you could measure both the amplitude and frequency of barrel vibration, say, for a PCP air rifle?

I'd guess someone has made something for the powderburner market, but I don't know of anything.

I would imagine something that connects to a cell phone would be pretty useful and sell pretty well, at least in the precision shooting crowd.

Maybe something that sits beside the rifle and uses high-res LIDAR or some simple laser device would be more appropriate.

 

[daddypaddy]

passive piezo electric dampeners

 

[Airgun-hobbyist]

The high-end golf club manufacturing industry uses something that measures frequency. It's been years since I read about it, so you'll have to get Google to give you an answer as to the product there.

 

[EquivalentDelta]

You’re looking for an accelerometer. They can be pricey.

 

[delooper]

The high-end golf club manufacturing industry uses something that measures frequency. It's been years since I read about it, so you'll have to get Google to give you an answer as to the product there.

I think my dad wrote the first research paper where accellerometers were used on golf clubs, back in the late 80's or early 90's (first international congress of golf in St. Andrews). But I don't think his ones were as sensitive as what we'd need on a barrel.

But yes that's what I was thinking, I just don't know much about where to find the right kind, and my dad has been out of the business too long.

Aha, found one: https://www.mitchellgolf.com/shop/r...ex-2-0-frequency-meter-w-portable-base-plate/

About $900.

 

[BlackICE]

Excella marometers can range from very inexpensive to very expensive. The expense goes up as the Precision of the measurement goes up and the conversion rate goes up. If all you need is a 10-bit conversion at about 5,000 samples a second not too expensive.

 

[subscriber]

What you measure will depend on where the sensor is mounted: Nodes will read low, because you are between sections that vibrate at large amplitude. Heavy sensors will alter the barrel vibrations. Some mounting systems may damp vibrations. So, there is more to this than throwing money at accurate sensors.

Some may suggest that the last inch of barrel is more important, because where that is pointing when the pellet leave the muzzle is what really matters.

High speed video may help to see if the projectile leave the muzzle in the middle of a "sweep", or at peak deflection. Peak acceleration does not tell the full story. You need to analyze the data to understand what it means. Barrel (muzzle) displacement, velocity and acceleration all matter.

 

[Troy Bakel]

Does anyone make a light-weight high-frequency motion sensor that would be suitable to mount on a barrel, so that you could measure both the amplitude and frequency of barrel vibration, say, for a PCP air rifle?

I'd guess someone has made something for the powderburner market, but I don't know of anything.

I would imagine something that connects to a cell phone would be pretty useful and sell pretty well, at least in the precision shooting crowd.

Maybe something that sits beside the rifle and uses high-res LIDAR or some simple laser device would be more appropriate.

Study on barrel vibration characteristics of typical sniper rifle - Extrica

The firing accuracy of sniper rifle is significantly affected by the barrel vibration induced by shooting load. The barrel vibration is an important parameter needing to be precisely controlled, whose measurement is less studied before. The vertical vibration characteristics of sniper rifle...

www.extrica.com

Link to barrel vibration study. The study used high speed photography so as not to influence the results with barrel mounted sensors.

There are actually 4 more studies on the subject that I found and they each used high speed photography for measuring the vibration but each used slightly different models to calculate the different harmonic amplitudes and speed and number of oscillations from chamber to crown and back as well as orders of distortion.

I have yet to find a study that is PCP specific. Maybe barrel vibration is not an issue in PCP rifle barrels! I say this based solely on world championship events in Benchrest, FT, and national events in PRS - NL22 where I cannot find one top level PCP shooter using an harmonic barrel tuner.

 

[Jaxjax]

I have yet to find a study that is PCP specific. Maybe barrel vibration is not an issue in PCP rifle barrels! I say this based solely on world championship events in Benchrest, FT, and national events in PRS - NL22 where I cannot find one top level PCP shooter using an harmonic barrel tuner.

I found this interesting. Not a measurement device just some math.