Ballistic Gelatin tests are they reliable?

[tipoc]

A little more from Federal...

http://le.atk.com/downloads/catalogs/EFMJBrochure.pdf

http://le.atk.com/downloads/catalogs...sertPoster.pdf


tipoc

[Mystro]

Yes,yes...!
Experience in hunting all around the country has taught me this exactly.
There is no magic bullet for every situation. There is too many variables.
The industry implying a performance guarantee is what drives me crazy. Newbies see this and think its the gospel truth and gives a false reality.

Its the same as saying.... wearing your seat-belt will guaranties your survival in a car wreck.

From Tipoc:

Nothing, not gel, not computer models, not testing on live animals, not studying autopsy reports, not after action reports from cops, can predict how a bullet will perform in the real world.

[Derbel McDillet]

The test of the wound profiles’ validity [as depicted in properly prepared and calibrated 10% ordnance gelatin] 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 [observed in properly prepared and calibrated 10% ordnance gelatin].

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.

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

[tipoc]

Its the same as saying.... wearing your seat-belt will guaranties your survival in a car wreck.

Well yes, no guarantee. But it's more likely you will survive if you wear one. Statistically more people survive because of them.

In the same way the best indicator we have for bullet performance is ballistic gel. The tests can't predict exactly what your bullet will do. But it can enable the shooter to select a bullet that is more likely to produce the results they want.

tipoc

[db4570]

From the Martin L. Fackler book: "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."

My point exactly. Let's say we assume ballistic gel is the equivalent of animal tissue. When was the last time you shot a boneless animal? I haven't hunted jellyfish in a while. Any good shot on any mammal is going to have to pound it's way through some pretty tough bone before getting to the vitals.

Don't get me wrong. I think ballistic gel is cool stuff and is useful in certain ways. But I think bullets expand in gel a whole lot differently than they do against a bone.

All this stuff is still a bit mysterious. For instance, the Speer chart that Tipoc references is really weird. If I am reading it right, the bullets that penetrate a hard barrier before hitting the gel actually penetrate further into the gel. Very counter-intuitive.

I also think Mystro's hunting experience he references is valuable and wise. It's sobering to think about the gruesome realities of self-defense shooting, however better than the alternative that might be.

David

[T-90]

I look at ballistic gel tests in the same manner as I look at automobile statistical performance. A lot of the results are based on controlled environments. They work as a guide and give you an idea of a products performance, but are in no way absolute.

[tipoc]

All this stuff is still a bit mysterious. For instance, the Speer chart that Tipoc references is really weird. If I am reading it right, the bullets that penetrate a hard barrier before hitting the gel actually penetrate further into the gel. Very counter-intuitive.

Yeah you'll notice that both bullets at two different velocities penetrated 17" and 18" into the gel after penetrating steel plate. You'll also notice that they did not expand much compared to the bare gelatin, plywood, or denim covered bullets did, and that some deformation occurred. They acted as ball ammo might and penetrated the furthest.

Note also that the bullets that penetrated the auto glass looked deformed as well and did not expand. But there a good deal of energy was spent in bullet deformation and penetrating the tough material of the glass and penetration in the gel was 10.5 to 12".

But I don't think this is counter-intuitive at all given the nature of the material being penetrated. When bullets don't expand they work like ball ammo or a full wadcutter and penetration is enhanced.

This type of performance is fairly typical.

You can see this with the 9mm as well.

http://le.atk.com/ammunition/federal...ls.aspx?id=579

tipoc

[hartcreek]

I have seen ballistic gel testing and bone was included. With all the videos online you should be able to find it as I have.

[Double Naught Spy]

Its the same as saying.... wearing your seat-belt will guaranties your survival in a car wreck.

Not really. The IIHS does a myriad of tests to assess seatbelt performance and their testing has improved significantly over the years. We have gel tests, maybe slap a few layers of various weights of denim over the gel or a random bone inside the gel and that is about the extent of what most testing involves.

What we do is pretty simplistic.

[Derbel McDillet]

Let's say we assume ballistic gel is the equivalent of animal tissue. When was the last time you shot a boneless animal? I haven't hunted jellyfish in a while.

JHP handgun bullets are designed to expand in soft tissues. In a defensive shooting the kinds of tissues we’re trying to destroy are all soft tissues. These are reasons why bone isn’t normally used to test JHP bullet performance because: 1) JHP bullets aren’t designed to expand in bone – they just deform, and 2) the bullet’s terminal performance characteristics are entirely dependent on factors that cannot be controlled by the shooter (what bone is hit, where it is hit, angle of impact, depth of location along the wound track, bone density/thickness, etc.). The only terminal performance desired in bone, at least that I can think of, is for a bullet to blast through to reach vital tissues. Quite simply, performance in bone is what it is.

-- Shawn Dodson, http://www.firearmstactical.com/tact...3/0604-03a.htm

and...

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).

-- Duncan MacPherson, “Wound Ballistics Misconceptions.” Wound Ballistics Review, 2(3): 1996; 42-43 (see - http://www.firearmstactical.com/tact...3/0604-03a.htm )

[WIL TERRY]

THERE IS ONE THING OF WHICH I AM SURE : if we are ever attacked by water filled milk jugs, 10% ballistic gelatine, 20% ballistic gelatine, frozen bags of water, chunks of firewood, or bars of soap, we know EXACTLY what to load in our pistols to be totally prepared.

ME ?? I will listen first and always to a pal of mine who has put bullets in thirty three men in the line of duty and lived to tell about it. He was wounded three times, killed all three, and took out two assassin teams other times.

That does not include two other friends now deceased that put bullets in eighty one men between 'em and lived to tell about it. MOST INTERESTING !!! You might know these two.....maybe not.

The one singular thing ALL three man advised strongly : USE A REVOLVER AS YOUR PRIMARY WEAPON !!! Back-up-guns are whatever you want and two of 'em is an excellent idea.

[db4570]

Thanks, Derbel McDillet, for some very interesting information in your post. The explanation of shear versus inertial force is particularly useful.

David

[TimSr]

The "global warming theory" is based on one interpretation of results from a model.

Aside from all the other variables, I would veture that a group of experts in this science could also look at the same gel test results and come to varying conclusions.

To me, as others have stated, gel simulates a belly blast. Since the standard aiming point for self defense is the middle of the chest I would thnk that simulated ribs would need to be infront of the gel. "Average" bone/flesh computations do not work on expansion bullets as a rib would likely cause rapid expansion before going through flesh, and may alter its direction, while gel cause more linear expansion throughout the bullet channel in a straigher path.

[Double Naught Spy]

Thanks, Derbel McDillet, for some very interesting information in your post. The explanation of shear versus inertial force is particularly useful.

Here is another way to look at gel blocks as being representative of something other than animal tissue. I can push my finger, hand, arm through a gel block, but can't push them through a person.

I can tear a gel block in two with my bare hands, one as big around as me. I can't do that with another human, not even a little kid (not that I have tried to tear any little kids in two, lately )

The one singular thing ALL three man advised strongly : USE A REVOLVER AS YOUR PRIMARY WEAPON

What a silly unrelated thing to say in the middle of a gel test discussion.

[Derbel McDillet]

Since the standard aiming point for self defense is the middle of the chest I would thnk that simulated ribs would need to be infront of the gel. "Average" bone/flesh computations do not work on expansion bullets as a rib would likely cause rapid expansion before going through flesh, and may alter its direction, while gel cause more linear expansion throughout the bullet channel in a straigher path.

Royal Canadian Mounted Police performed extensive testing with pig ribs cast into gelatin blocks. The ribs had negligible effect on terminal performance.

[481]

The CPRC also did similar tests against pig ribs and issued rain gear with lead shot in #7 1/2, #4, and 0Buck sizes:

http://www.docstoc.com/docs/11179985...dnance-Gelatin