Resonance, ringing, recoil, smooth trigger pull and brakes

Sounds like a handful under one heading, however I had a play, collecting vibration data, measuring acceleration and G's on my gun, with and without a muzzle brake and found some other interesting stuff when I looked at the data.

Grab a coffee, this will take a while. I recently purchased a set of Recovib sensors to analyse a vibration problem at work. I was also aware of a friends work with recoil... these sensors were good to 15G so I though I would have a play.

This is one of the sensors... it attaches to the action using magnets, I attached one to the side of the action
Attachment 136186


Here we see the 6 shots, first 3 with the muzzle brake and last 3 with out....Blue "X" is inline with the barrel, green is "Y" Vertical and brown "Z" is horizontal. The acceleration with the brake is 15/10 and 8 mm/s/s without the brake it is 17, 15 and 13 mm/s/s... quite a measurable difference.

Attachment 136189

This one is the same data but instead of measuring acceleration it measures displacement or how far the rifle moved (below the line) 22, 22 and 31mm with the brake and 33, 31 and 34mm without the brake.

Attachment 136185


Where it get interesting is these next two, with and without the brake. recall reading a article... I thing it was a Ruger but maybe mistaken.. it had a small adjustable weight at the end of the barrel that you could tune out vibration... I think it was generally considered a gimmick however when you look at the below, you can clearly see with the brake, the barrel resonates and not without... interesting and warrants more thinking

Attachment 136192Attachment 136193


The time in this window is 1/100s of a second from trigger pull, I think primer igniting (small blue peak) and combustion (big blue peak)... what is interesting with this is how smooth the trigger pull is... this gear very sensitive and would detect anything that was not smooth as...
Attachment 136195

Complements to the shooter... not me. This is the nearly one second before the shot... the flat lines say it all

Attachment 136196

I think you are talking about the Browning BOSS system for tuning out vibration.

Will be interesting to learn more..

As for the gear, it is a true accelerometer with a somewhat limited data collection rate... good for big slow vibes ...a piezo crystal is better for higher frequencies and data collection rates.

Quote:

---

Originally Posted by Cigar

I think you are talking about the Browning BOSS system for tuning out vibration.

---

yes that was it....

Quote:

---

Originally Posted by mimms2

Varmint Al. It's in one of his pages I'm sure...

https://www.varmintal.com/a22lr.htm

---

Thanks Mimms2... that looks like it... I will have a good read of that when I get back from work later today....

Awesome! This is what I like seeing on the forums. Thank you LBD. :cool:

Was there an effect on precision with the resonance?

Quote:

---

Originally Posted by K95

Was there an effect on precision with the resonance?

---

I had not noticed the resonance at the time I was collecting data as we were only measuring recoil energy, it was not until I started looking at the data closely I noticed it.

It is something I will need to play with again in the future, however any long range or accurate stuff after I noticed the resonance is now done without the brake...

It'd still be very interesting to see what reloads of varying accuracy visually look like in terms of vibration ie. Is inconsistent vibration a factor for poor accuracy?

Very interesting. If I'm reading correctly this was all measured from the action? Reckon you could mount your accelerometer on the barrel itself somewhere closer to the muzzle - you may get a better picture of the barrel whip itself? The added weight on the barrel would itself change the harmonics, but may still be interesting.

Did consider that however I need either a flat surface for the magnets or an adaptor... but as you point out, it will alter the resonance of the barrel.

I recall seeing a diagram in an old reloading manual I thought was interesting. It discussed the two types of oscillation a barrel goes through on firing. One was the muzzle describing a circular path around its axis, the other was like a rope been shaken with nodes where the vibrations cancelled.
It talked about barrel tuners and load development to find a node of consistent stability.
If i remember correctly it said you can alter the barrel oscillation and frequency by changing bullet weight, or velocity till consistent groups are obtained.
Till I read this thread I'd forgotton about it, I must look through those old manuals again.

Very interesting - thanks for sharing. Have access to a portable accelerometer at work (Slamstick) so might have to have a play myself one day with my own data. Good unbiased way of establishing good trigger pull technique