CZ 457 MTR with Sensors To Measure Barrel Harmonics (Part 10) Slow Motion and Sensors

This is the slow motion video capture of the CZ457 barrel whiplash with accelerometer and proximity sensors mounted onto the barrel to measure the little barrel vibration that the camera cannot capture.

[@matthewkirk514]

This is definitely taken it to a new level.

[@TunerPlinker]

Hoping so. Definitely more data and results to collect.

[@TDub326]

You are taking open pipe physics to another level with barrel wave monitoring…. Nice series!!!

[@boerseun3023]

Well done. Finally someone that proves harmonics without a doubt. This was very informative.

[@Top_Autist]

I love your range setup

[@michaelhirsch4251]

I think this is a frequent experience. I had assumed it was due to smoke and/or unburned powder being “seen” by the chronograph but you make a good point it might also be incandescent gasses (muzzle flash). I’m either case I would expect the photo interrupter to work although this would need a test to confirm. Assuming it works, the interrupt pulse would occur a few hundred microseconds before your proximity sensor’s pulse if both are working as hoped. My guess is the prox sensor will be several milliseconds later.

[@jwoodshed1108]

Great job. Do you have plans for a video showing a tuner on the barrel? And make changes to the tuner to show how the scope sees the tuner setting change.

[@TunerPlinker]

Yes. This is just a preliminary test of the proximity coil and accelerometers. Still waiting for my chronograph PCB to arrive. Once I have the sensors all calibrated and working, I plan to take more data to help characterize the barrel harmonics and put on the tuner and show the differences in barrel harmonics and point of impact.

[@north4961]

Looking forward to your scientific results and explanation of the results. Well done👍 Sub’d & Liked 🇨🇦

[@TunerPlinker]

Thanks for the sub!

[@vincebelmonte7710]

Great never seen so much info on a video thanks Tuner Plinker

[@TunerPlinker]

Thanks. This is just the beginning. Wait till I get all my sensors working and when my diy chronograph PCB arrives in a few more weeks.

[@vincebelmonte7710]

@@TunerPlinker Can't wait for the science, thanks all the best

[@michaelhirsch4251]

I suggest you try GP1A57HRJ00F (Sharp), (Digikey 1855-1043-ND). It is a slot type optical interrupter with sub microsecond rise and fall times. It has a 10 mm open space so the bullet can easily pass through the slot and create a signal. Try attaching it to your muzzle and I'll bet you find what you believe to be the bullet signal from you proximity sensor is in fact several millseconds delayed. Barrel time, I believe, is much less than suggested by your measurements

[@TunerPlinker]

Thanks for the suggestion. I will look into it.

[@TunerPlinker]

Do you know if muzzle flash affects the bullet detection? I have a optical chronograph that won't work unless it is at least 10 ft away from the muzzle. That's the reason I designed my 15MHz solenoid sensor.

[@chuckchuckhanner9538]

It would be interesting to see the effects of using a barrel tuner in your experiments.

[@TunerPlinker]

Yup. Working on it. Just finished printing the sensor mount for the tuner. When I have good data, I will post another video.

[@lamarmottedesinternets5134]

Hi, great video. I've been studying this phenomenon as part of a project for my entrance exams for engineering schools. I'm studying how the barrel behaves (and the influence of a flotting barrel on precision). If you have any ways through which I can contact you, I'd be glad to talk to you more about your experiments. Thanks again for the great video.

[@TunerPlinker]

Let's chat via my email [e-mail].

[@Longshothawk]

This is great. It seems your focus is on 22lr, but would this setup work on a center fire rifle?

[@TunerPlinker]

It will work on any rifle.

[@davidsalsedo6765]

Fantastic work! Barrel tuner testing?

[@TunerPlinker]

Thank you. Yup, this is for barrel tuning.

[@kiyoshiishihara6748]

I knew the effects of barrel vibrations for many years But recently I realized pre departure recoil effects accuracy greatly from hand gun shooting heavy bullets My question is how much of pre departure forces are there from full power 45 ACP ?

[@TunerPlinker]

Not sure how much pre departure forces are from 45 ACP. If it is anything like my CZ 457 rifle, most of the recoil happens after the bullet has left the barrel.

[@charlesking8542]

Between pulling the trigger and the bullet exit, are the vertical cycles occuring at the speed of sound longitudinaly along the barrel>

[@TunerPlinker]

From the data I have gathered so far, and it is still in the early stages, the vertical cycles are not at the speed of sound. I can follow-up with you when I have all the kinks worked out with my sensors.

[@charlesking8542]

@@TunerPlinker those sure look like the fourth harmonic of the speed of sound.

[@timothym2241]

How do you know you are measuring barrel whip, and not the entire rifle vibrating?

[@TunerPlinker]

The accelerometer sensor spikes violently after the trigger is pulled with a live ammo. Without a live ammo, the sensor data is very quiet.

[@mrawesomeness8558]

The things you do for science.... 😂❤

[@TunerPlinker]

It's all for the sake of science.

[@TunerPlinker]

And spent a pretty penny for it too with all the prototypes.

[@roqcdatamanagement6905]

on the vertical accelerometer trace, what do you think the 'flatline' sections are ? they appear to be prevalent before the bullet leaves the barrel ?

[@TunerPlinker]

The first two capture had flat lines because of the scope scaling is set too low. It was clipping. The third plot was definitely not clipping but also has flat lines. This indicates that the acceleration is constant during that period. I need to analyze the raw data to figure out what's happening. Wondering if the barrel is not free floating because of big swings.

[@roqcdatamanagement6905]

@Tuner Plinker the 4 flatlines on the third capture all appear to have the same value and no or very lityle noise - could they be drop outs of the acellerometer signal ? I have problems believing the barrel stops moving then starts vibrating again.

[@roqcdatamanagement6905]

@Tuner Plinker the 4 flatlines on the third capture all appear to have the same value and no or very lityle noise - could they be drop outs of the acellerometer signal ? I have problems believing the barrel stops moving then starts vibrating again.

[@TunerPlinker]

@roqcdatamanagement6905 I was a bit perplexed about the flat line too. This is very preliminary data just to test out the sensors. Will need to crunch the data to figure out the position of the barrel. It will likely tell us what is happening.

[@TunerPlinker]

​@roqcdatamanagement6905 It looks like the shock is too much for the accelerometers and it clipped it. The sensor overange turned on to protect the sensor! This sensor is rated to +/- 100g! This is incredible. The shockwave is huge!

[@chrisf2037]

If the barrel oscillates in a figure 8 shape that would corelate to the higher vertical movement, and the less horizontal. Would you be able to estimate where on the vertical acceleration graph the bullet is actually leaving the muzzle? I think the theory in tuning a rifle being that you are trying to find a load that exits the barrel around the top or bottom of the figure 8 pattern would match up with timing the bullet to leave during the moment of minimum vertical acceleration (top and bottom where it changes direction). Would be really interesting to see if you could correlate the bullet exit point with respect to vertical acceleration to accuracy. With 22LR trying different ammos would put you in different barrel exit locations with respect to acceleration. That and if you could pair this up with super slow motion camera would be really interesting.

[@TunerPlinker]

After collecting some preliminary data on the gyro and accelerometer sensors with live rounds, I have found some issues with both the gyro and accelerometers. I believe I have fixed the issue with the gyro and in the process of replacing with two new accelerometers. If the sensors work, that is, if the gyro data correlates with the accelerometers, I can definitely map out the muzzle position/rate of angular change when the bullet exits the muzzle. I like your feedback about the figure pattern. I can definitely plot the path of the muzzle given the x and y accelerometer data.

[@chrisf2037]

Have you watch any of Erik Cortinas Believe the Target interview series he does? He has interviewed some really interesting people in the shooting world. The latest one, Eric Higgins, is interesting in that he is trying to use high speed cameras with some software applied to exaggerate movement to determine what the barrel really does.

[@TunerPlinker]

@chrisf2037 The measured vibration is very tiny. I am not sure it the camera can actually measure that tiny of movement. Here's my latest update: The new accelerometers works a lot better and no clipping is observed. However, the gyro sensor is not correlating withe the accelerometers. The reason being is the gyro sensor that I am using is not sensitive enough and as a result, it is very noisy. The good thing is the accelerometers are very consistent and more reliable. The more sensitive gyro sensor by itself costs $2k. I would not be able to afford it for this experiment unless Analog Devices give me a free sample. I have a pretty good relationship with Analog Devices, but don't want to stiff them for free samples. Anyways, I will be updating my Matlab scripts to finalize the data collections and give you guys a preview of what I have been quietly working on. Stay tune....I know it's a Long wait.

[@sidekickbob7227]

​@@TunerPlinkerThe highspeed film is heavily prossesed by software, and the vibrations invisible for the human eye are supposed to be exaggerated to a visible level. Very interesting podcast. I can also suggest the Hornady podcast with one of the barrel guru's (Don't remember the name). He discard the description of barrel harmonics, and introduce "forced barrel vibrations" . If you haven't already listened to the podcast, I would higly recomend you to do so. Your testing is very interesting, and I hope you will continue making videos.

[@TunerPlinker]

@sidekickbob7227 If you have the link to the podcast, I would be interested in tuning in. From the accelerometer sensors I have collected, the shockwave is mostly due to violent powder explosion inside the barrel. I don't see any barrel harmonics till long after the bullet exits the crown. What I am referring to is the barrel self resonant frequency or ringing or some people refer to it as barrel harmonic. So yes, I do agree that barrel harmonic play less of a role. The reason is because the barrel harmonic frequency is much lower than the shockwave frequency....and I did not measure any of the low frequency while the bullet is inside the barrel.

[@johnhess351]

Admirable use of test equipment, but usefulness of data is nil. We know that there is whiplash in the barrel and you have re-confirmed it. The usefulness would be the azimuth and magnitude of the eliptical ringing. The rifle apparently has an indexed barrel since very little lateral movement was detected, but cannot tell from your measurements what the direction or the magnitude of the lateral deviation is. That is the useful and needed data to make barrel accuracy comparisons. Additionally, it would appear that your fixturing may not be neutral and could be adding feedback negative or positive. The easier method would be to optically produce a wave form on a screen or photographic plate by means of projecting beam from barrel. ie laser in breech and externally excited impulse. You have achieved great resolution of a low precision measurement. Relative eyeball comparison of waveforms is all that is necessary here.

[@TunerPlinker]

There were a lot of issues with the sensors clipping. I have since replace with different sensors and resolved the clipping issue. You can see the final results by fast forwarding to part 12 to 14 of the video.