Shockwave Shadows in Ultra Slow Motion

Discussion in 'Main Message Board' started by Texas10, Nov 3, 2018.

  1. Texas10

    Texas10 Gold $$ Contributor

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    I really got a kick out of this. Supersonic shock waves videoed in super slow motion, in both supersonic bullet speeds, and subsonic speeds. 50 cal vs 300 black out. You can also see powder particles emitted from the muzzle with attached shock waves, and a curious area of turbulence left behind the bullet path, also obvious is the yaw on the subsonic bullet.

    Really interesting video, and the best part is they plan to do more on the subject.

    Hope you enjoy!

     
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  2. sdean

    sdean Silver $$ Contributor

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    You should get out more often. Was on here yesterday.
     
  3. group therapy

    group therapy Silver $$ Contributor

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    cool, thanks for posting!!!!:)
     
  4. rammac

    rammac

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    What I like about this video is that it proves that it proves that recoil does not happen until after the bullet has left the muzzle - contrary to what the armchair experts always claim.
     
  5. rwj

    rwj Silver $$ Contributor

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    Please explain...
     
  6. tuttlefarm

    tuttlefarm Silver $$ Contributor

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    Really cool, glad to see an article that we can actually learn something.
     
  7. 47WillysGuy

    47WillysGuy Gold $$ Contributor

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    Gas pressure is equal in all directions while the bullet is in-the barrel but when it leaves the barrel, not equal anymore. The gas is leaving the barrel out the muzzle and is pushing firearm and you rearward.

    That’s my understanding in vey layman’s terms.
     
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  8. Hino895

    Hino895

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    Yep way cool.
     
  9. rwj

    rwj Silver $$ Contributor

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    What keeps the case from moving rearward as the bullet is being propelled forward towards the muzzle?
     
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  10. rammac

    rammac

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    It really needs no explanation to prove that recoil only happens after the bullet leaves the muzzle, just watch the end of the video where he fires a revolver. You will clearly see that the muzzle doesn't move until after the bullet leaves the muzzle.

    The mistake most laypeople make is that they don't understand the basic application of Newton's Laws. In order to apply Newton's Third Law ("When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.") you have to define the system that you are applying the law to. In other words, when you apply the third law to a gun and it's recoil you must only look at the parts that make up the system. In the case of the movement of a gun the system is the gun and the cartridge, we usually exclude the shooter because that just complicates what is happening with the gun and the bullet (the bullet being part of the cartridge)

    With the system being defined as the gun and the cartridge we can see some pretty obvious things right away;
    1. The bullet is far lighter than the gun.
    2. Force of the hot EXPANDING gasses must be included in the system.

    I emphasized the word expanding because the act of gasses expanding creates force if it's opposed by an object.

    At any rate, as the bullet moves down the bore all of the forces in the defined system are contained inside the gun. On the one side of the equation you have the expanding gasses and the bullet movement that apply forces in one direction and then you have the counter forces of the gun's mass on the other side of the equation. The two sides of the equation equal out and the center of mass of the gun doesn't move. Every force that moves in one direction inside the gun is opposed (as per Newton's Third Law) by an equal and opposite force, that means that it's impossible for the center of mass of the gun to be moved in any direction by the forces inside the gun because all of the forces inside the system (the gun) are opposite and equal, there is no resultant force any direction.

    But when the bullet leaves the muzzle you change where the forces are applied, they are no longer being applied inside the system, now you have force being applied from outside the gun and the gun can be moved by this outside force.
     
    Last edited: Nov 4, 2018
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  11. rammac

    rammac

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    Obviously it's the mass of the gun that prevents the force of the case from moving the entire system rearward. But remember that the mass of the case is nowhere near enough to overcome the counter force of the gun's mass so the system (the gun) doesn't move.
     
  12. chkunz

    chkunz Gold $$ Contributor

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    We may not be able to see a small movement, we would have to instrument the gun with instrumentation that is capable of measuring any small movement to be sure. Even a small movement would change the point of impact of the bullet. It would take instrumentation capable of this measurement to know for sure.
     
  13. chkunz

    chkunz Gold $$ Contributor

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    The center of mass of the system (gun, bullet, powder) changes as the bullet and gas move down the barrel, the change is small for some gun systems but it does change.
     
  14. rwj

    rwj Silver $$ Contributor

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    Place an unconstrained single rod end pneumatic cylinder on a frictionless surface then apply internal pressure... what moves - the cylinder body, the piston/rod or both?
     
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  15. tuttlefarm

    tuttlefarm Silver $$ Contributor

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    There is a few things left out of the equation, bullet compression in the bore and friction. The force to move a compressed bullet is a lot more than the rifle weighs
     
  16. alinwa

    alinwa

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    L-O-Freakin'-ELL!!!!

    What this post proves is that different eyes see different things!

    Amazing deduction..... flatout amazing is all's I can say.....
     
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  17. alinwa

    alinwa

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    This Destin guy who made the video is super accessible...... My kids have posted with him.

    What you'se really need to do is ask him this question, and offer your analysis!

    'Course he's only a licensed Engineer who quit a huge job to become The Dork With The Camera so what does HE know??!

    THAT conversation would provide fuel for a few more amazing videos......
     
  18. Robbie610

    Robbie610

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    If recoil doesn't start until the bullet leaves the muzzle, why does a slower, heavier bullet impact higher than a faster, lighter bullet? With target at 25 yds, in a .45 cal pistol, fire a 230 gr bullet at 830 fps. Then fire a 185 gr bullet at 900 fps from the same gun. Watch where they impact. What accounts for the difference?
     
  19. Doug Beach

    Doug Beach Silver $$ Contributor

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    Load a 6” .44 with a single 300gr round. Locate the center of gravity.
    Insert a 300gr weight into the muzzle of that same revolver, when empty.
    Locate the center of gravity.
    The new center of gravity will be significantly different than the first one.
    Movement of mass has occurred, prior to the bullet leaving the muzzle.
    Movement equals action.
    For every action, there is an equal and opposite reaction.
    A gun is in motion, prior to the bullet’s exit. This is mathematical fact, and was demonstrated by Hatcher, a long time ago. Read his book.
     
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  20. Bob Sebold

    Bob Sebold Gold $$ Contributor

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    If he is looking for things to test... I would like to see the same bullet and load tested with one bullet untipped and the other tipped. Preferably 7mm Berger 180's at around 2800 fps.
     
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