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JHP expansion test

Discussion in 'General Gun Discussions' started by gfpd707, Jun 24, 2010.

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  1. gfpd707

    gfpd707 Member

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    I want to compare some ammunition I have. What is the easiest way to do this? I have seen the milk jugs filled with wet newspaper but that seems like it would take forever. Would water work or would the round fly apart? The gun I would be using is a glock 19
     
  2. Ridgerunner665

    Ridgerunner665 Member

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    This may sound kinda weird...but it works with handguns (up to 44 Mag anyway), and is safe.

    Get a 5 gallon bucket, fill it with water (do not put a lid on it)...and stand on something to get your legs above the bucket (just in case). Fire straight down into the bucket of water...your bullet will be laying in the bottom of the bucket expanded as pretty as a picture.

    I have known a few cheap hollowpoints to lose their lead core and it penetrate the bottom of the bucket...but VERY few have ever done that.

    You may get a little wet...but its a fast easy way to do it.
     
  3. gfpd707

    gfpd707 Member

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    I wondered about this. I was convened that it would just blow through the bottom of the bucket.
     
  4. Ridgerunner665

    Ridgerunner665 Member

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    It won't...not if its a hollow point (or any other expanding type bullet)
     
  5. Ed Harris

    Ed Harris Member

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    Pistol bullets which don't expand, such as .38 Special SWCs dent the bottom of my 96 gallon plastic wheeled trash cart when filled full of water. A 5-gallon bucket is not enough, even .32 ACP JHPs which fail to expand will zip right through. You can buy a sturdy 96-gallon Toter brand trash cart at Home Depot, fill it to overflowing with water, cover the opening with a trash bag to reduce spash back, and stand on a step ladder to shoot down into it. Then empty it out to recover your bullets. When not using it to test ammo, it is really a GREAT trash can!
     
  6. Wahoo95

    Wahoo95 Member

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    55gal drums of water work well too.
     
  7. Ridgerunner665

    Ridgerunner665 Member

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    I've used a 5 gallon bucket for everything from 32 auto on up to 44 Mag....has always worked for me.
     
  8. ccsniper

    ccsniper member

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    I know 55 gallon drums work and they are dirt cheap. There are vids on youtube where a guy does a bunch of expansion tests with different typs of ammo. You might want to check him out, he may have already done the ammo you are gonna try.
     
  9. John Wayne

    John Wayne Member

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    I have never heard of filling a milk jug with newspaper. Milk jugs filled with water are fun to shoot, but you usually won't be able to recover the bullet unless you have several of them in a row.

    I took about 16 old phone books and a cardboard box used to hold legal folders (holds about 16 phone books in series). It works pretty well, just wet the phone books down really good first.
     
  10. lions

    lions Member

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    I've used milk jugs filled with water. It usually only takes 3 to stop a JHP, sometimes 4 though. I usually line up 5 just to be sure. It is interesting to get to see what an expanded bullet looks like and as always, milk jugs are great reactive targets.
     
  11. Shawn Dodson

    Shawn Dodson Member

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    Suggested by Dr. Fackler:

    One water filled milk carton and one box densely filled with polyester pillow filling. Shoot through the milk carton. The polyester fibers in the box will stop the expanded bullet without damaging it.
     
  12. GRIZ22

    GRIZ22 Member

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    Testing expansion in the ways related will only be valid if you intend to be fighting water jugs, water barrels, wet sand, newspapers, etc. The industry uses ballistic gel to test expansion and that really only proves expansion in...ballistics gel.

    Pick quality ammo that shoots well in your gun with a JHP and it will do the job.
     
  13. ArtP

    ArtP Member

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    As I read further and further down, I kept hoping someone would wise up. My faith in mankind is restored.
     
  14. ccsniper

    ccsniper member

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    I think he just wants to look at the bullets expansion and see how each differs.
     
  15. Shawn Dodson

    Shawn Dodson Member

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    Extract from “Wound Ballistics Misconceptions.” (Duncan MacPherson, Wound Ballistics Review, 2(3): 1996; 42-43)

    When a bullet is penetrating any material (tissue, water, air, wood, etc.), the total force the bullet exerts on the material is the same as the total force the material exerts on the bullet (this is Newton’s Third Law of Motion). These forces may be represented as a combination of shear forces and inertial forces (don’t be concerned if these words sound too technical – the concepts are easy). Shear force may be thought of as the force that resists deformation; if you push on a wall you are creating shear forces in the wall material that resist your push. If you push your hand down very slowly on a water surface, you feel no resisting force; this is true because a liquid cannot support a shear force….

    You can fan your hand back and forth in air quite rapidly because there seems to be no resistance, but a similar fanning motion cannot be done nearly as rapidly underwater because moving the water can take all the strength you can muster. The forces that resist the movement of your hand in water are inertial forces….

    A bullet penetrating a soft solid (tissue or a tissue simulant like gelatin) meets resistance that is a combination of shear forces and inertial forces….

    …Anyone who has worked with gelatin knows that a finger can be pushed into gelatin with a force of only a few pounds; this force is similar to the resistance to a finger poked into the stomach, but the tissue does not fracture as easily as gelatin does. A finger poked into water does not meet this kind of resistance, which is due to shear forces. Penetration of a 9mm bullet at 1000 ft/sec is resisted by an inertial force of about 800 pounds; it is obvious that the presence or absence of a 3 to 5 pound shear force makes no practical difference in the penetration at this velocity. This also explains why the fact that gelatin fractures more easily than tissue does is not important.

    The extension of these dynamics to soft tissue variation is obvious. Different types of tissue present different resistance to finger probing by a surgeon, but the surgeon is not probing at 1000 ft/sec. Different tissue types do have differences in the amount of shear force they will support, but all of these forces are so small relative to inertial forces that there is no practical difference. The tissue types are closer to one another than they are to water, and bullet expansion in water and tissue are nearly identical at velocities over 600 ft/sec where all bullet expansion takes place (See Bullet Penetration for a detailed explanation of bullet expansion dynamics).

    Since inertial forces depend on accelerating mass, it makes sense that these forces should be lower at lower velocities (because the penetrated material cannot be accelerated to a velocity higher than the bullet). Shear forces have little velocity dependence, and as a result, shear forces are a much larger fraction of the total when bullet velocity is below the cavitation threshold. This low velocity effect is the reason that total bullet penetration depth is much different in water and in tissue or a valid tissue simulant.

    As a result of the penetration dynamics, most soft solids with a density very near soft tissues (i.e., near the density of water) are satisfactory tissue simulants when shear forces are not important. However, total penetration depth depends significantly on dynamics at velocities below 400 ft/sec, so most materials do not properly simulate penetration depth. The total bullet penetration depth in tissue and a valid tissue simulant should be the same; standard practice is to use calibrated gelatin to insure this. In effect, gelatin calibration is done to ensure that the shear forces in the gelatin are the same as in typical soft tissue (as described in Bullet Penetration, the technical parameter used in the dynamic is viscosity).


    Extracts from “The Wound Profile & The Human Body: Damage Pattern Correlation.” (Martin L Fackler, MD, Wound Ballistics Review, 1(4): 1994; 12-19)

    The test of the wound profiles’ validity is how accurately they portray the projectile-tissue interaction observed in shots that penetrate the human body. Since most shots in the human body traverse various tissues, we would expect the wound profiles to vary somewhat, depending on the tissues traversed. However, the only radical departure has been found to occur when the projectile strikes bone: this predictably deforms the bullet more than soft tissue, reducing its overall penetration depth, and sometimes altering the angle of the projectile’s course. Shots traversing only soft tissues in humans have shown damage patterns of remarkably close approximation to the wound profiles.

    The bullet penetration depth comparison, as well as the similarity in bullet deformation and yaw patterns, between human soft tissue and 10% ordnance gelatin have proven to be consistent and reliable. Every time there appeared to be an inconsistency…a good reason was found and when the exact circumstances were matched, the results matched. The cases reported here comprise but a small fraction of the documented comparisons which have established 10% ordnance gelatin as a valid tissue simulant.
     
    Last edited: Jun 25, 2010
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