Audio sign of pressure

Discussion in 'Reloading Forum (All Calibers)' started by Fliers, Mar 12, 2019.

  1. Fliers

    Fliers Gold $$ Contributor

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    In working up loads, the bang gets really loud and sharp just prior to craters primers. I'm my recent test, they were really loud, but primers were all mostly fine. Does anyone use sound as a pressure indicator?
     
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  2. AJC

    AJC

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    No. But you may on that load if the indicator is repeatable and consistent. Not something I would put a lot of faith in.
     
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  3. hboothe

    hboothe

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    I wouldn't trust the report of the firearm because it's kind of subjective. I can't tell how loud the sound is and certainly cannot measure it in any scientific manner, let alone my ears. I'm no expert and I don't know everything, but I trust primers and ejector marks and chronograph numbers compared to professionally-published load data.

    I cannot quote the source because I don't recall where I encountered it (but it seemed legit...maybe one of the reloading manuals, but I cannot say) but I seem to recall that there was some source that reported that some pressure signs abate a little as the pressure approaches CATO (catastrophic failure). I dunno. I'd be careful. I think chronograph data would be your best bet and try to compare those results to published load data or similar-projectile factory loads.

    FWIW.

    --HC
     
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  4. Sniper338

    Sniper338

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    Bring on the popcorn....
     
  5. Homerange

    Homerange

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    Audio sign of pressure = when the shooter says; hell that kicked ! :D
     
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  6. KMart

    KMart Gold $$ Contributor

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    This is an interesting conversation here.
     
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  7. Texas10

    Texas10 Gold $$ Contributor

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    Sorry....what did you say?
     
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  8. Fliers

    Fliers Gold $$ Contributor

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    Just looking for some consensus.. I haven't noticed any hard bolt lift, but definitely louder and high pitched report as I went up in charges. I didn't see any ejector swipes and wasn't sure if cratering was may be due to needing a bushing. Of course, maybe I'm just not good enough at seeing the swipes either.
     
  9. lb-ft

    lb-ft

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    One of my 308 bolt guns has a tight factory chamber (Sauer 202). When still within published data specs w/175 SMK load workup, rifle made a weird twang harmonic noise on the last three shots. Close inspection of fired Lapua Brass revealed excessive pressure on that final volley. Load reduced, accuracy exceptional, sound & vibration has not recurred. Odd for sure
     
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  10. Nature Boy

    Nature Boy Gold $$ Contributor

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    The sound of a mallet beating on a bolt handle?
     
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  11. Whit holman

    Whit holman

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    Yes I have seen that to
    To me the recoil is different also
     
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  12. mauser284

    mauser284

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    No! Human hearing is garbage and not remotely reliable. You would need to have a very accurate transducer and a large data set to use sound as a reliable predictor of pressure.

    I can easily play games with peoples beliefs and with sound it is too easy. We do not hear with our ears and we do not see with our eye's rather the brain takes sensory input and creates reality around itself inside the mind. That is why it is so easy to fool the sense because it comes down to the persons brain. Once you know what assumptions the brain makes it is a piece of cake. That is also why you can not fool everyone with the same deceptions but you can fool most people.

    It is not that you might not be able to recognize when something is not right it has to do with how consistently you can tell and how close to failure you need to be to detect it!

    There is a reason why we do not use eyesight to judge the proper temp. for steel forging, annealing or any other critical engineering characteristic! We use machines that are calibrated that can consistently and repeatedly read and record the data for use.
     
  13. jds holler

    jds holler Gold $$ Contributor

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    Seems like there oughta be a phone app that reads decibels.:) jd
     
  14. newbieshooter

    newbieshooter :-) Silver $$ Contributor

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    don't use it much - but this is the one on my iPhone.

    upload_2019-7-7_0-43-26.png upload_2019-7-7_0-43-55.png upload_2019-7-7_0-46-10.png
     
  15. Raythemanroe

    Raythemanroe Bullet Whisperer Silver $$ Contributor

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    Ear protection?

    Ray
     
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  16. spclark

    spclark Gold $$ Contributor

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    There’s a bunch out there. Newbieshooter showed you his, here’s mine:
    upload_2019-7-7_8-12-25.jpeg
    - but understand you’re trying to measure loud sound (high pressure waves really) over a very brief interval so the mechanism on a smartphone may not be responsive enough to register peak values.

    I’ve never tried comparing muzzle blast reports from my rifles but have casually measured reports from shooters I’ve scored for during competitions. It does work but having no way to ‘calibrate’ my system I’m wary of drawing too much from the numbers I get.
     
  17. Raythemanroe

    Raythemanroe Bullet Whisperer Silver $$ Contributor

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    I have heard people say you can hear the sound of the shrapnel going through roof on the firing line..

    Ray
     
  18. varget204

    varget204

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    AAAAAYYYYYYYAAAAA ?
     
  19. mike a

    mike a 6BR Rocks Gold $$ Contributor

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    I don't know about guns but I can tell by the sound of my wife's voice prior to her blowing a primer. Mike
     
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  20. Dusty Stevens

    Dusty Stevens COVFEFE- Thread Derail Crew Gold $$ Contributor

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    Once your powder burn is perfect over the length of your barrel it does have a sharper crack. Go to a shortrange br match and you can tell on a ppc which ones are tuned
     
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