Tennessee Gentleman
New member
Agreed. John, I just wish it hadn't happened to those agents. Duty can be a heavy burden but they bore it well.
Terminal ballistic question
- Thread starter heyduke
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David Armstrong
Moderator
That is the goal, and to best achieve that goal ammo designers work within certain parameters. For example (just making up number here) maybe a 230 grain JHP with a particular bullet design works best at around 800 fps, but if you bump that same round up to 1000 feet per second it tends to expand too quickly and does no tpenetrate very far. But if you slow it down to 700 fps it doesn't expand well, so it works like a hardball round and penetertes a whole lot. Another manufacturer's 230 JHP uses a different jacket material and point design, so it works better at 700 fps. You push it real fast and it starts to have a shallow wound pattern.
CARGUY2244
Moderator
there's significant contrast in skill sets between tactical operators and field investigators.
the former constantly trains for armed engagements, thereby increasing the likelihood of correct shot placement, the use of cover, and the ability to close ground effectively to stop a conflict.
the latter visits the range, standing statically, firing 100 rounds a month.
leo's, and the agencies they represent, often fall into the mindset of "we have badges, legal authority, and power of the agency behind us. nobody can challenge us." unfortunately, the bogies don't always know those rules. had p and m been confronted by 1 single trained operator who was both mentally prepared and physically trained for said engagement, they would've been neutralized in short order.
this was anything but a product of ballistics.
the former constantly trains for armed engagements, thereby increasing the likelihood of correct shot placement, the use of cover, and the ability to close ground effectively to stop a conflict.
the latter visits the range, standing statically, firing 100 rounds a month.
leo's, and the agencies they represent, often fall into the mindset of "we have badges, legal authority, and power of the agency behind us. nobody can challenge us." unfortunately, the bogies don't always know those rules. had p and m been confronted by 1 single trained operator who was both mentally prepared and physically trained for said engagement, they would've been neutralized in short order.
this was anything but a product of ballistics.
And to expand upon the problem bullet designers face, tissue isn't tissue, necessarily. Unlike ballistics gel, our bodies are not tidy and homogenous. There are many different types of tissue a bullet might encounter on its path through a body - skin tissue, muscle tissue, body fat, vascular organs, "stretchy" organs, bone, etc. The path and behavior of a bullet isn't precisely predictable because it's impossible to know exactly which tissues it will traverse, as each of us is built differently. Terminal ballistics will always be an inexact science insofar as knowing exactly what WILL happen when lead meets flesh; it is, however, quite good at describing the phenomena which occur once the interaction has already occurred.
Kinetic energy
The Kinetic energy a 2000lb big Ford or Gm vehicle at say 40 MPH, probably surpasses some artillery shells! It was a company car yes?
The vehicle they were following was a match to the info they had, and going at a slow speed, weapons observed, IMO it should have been seat belts tight, swing wide, nail drivers door!
Windows open on passenger side of FBI vehicle, shoot from inside, driver and rear seat passenger exit. Advice to the shooters in FBI car, do not shoot the ones with FBI on their backs!
A friend of mine, for some 35 years (he can retire any time) works for a Police Dept. that has 870s and AR15s in the shop, he is the only one on the shift who books one of each out every day he works, the same two he has shot a bunch of rounds through. They can only ride in cases in the trunk.
He tells his Buddy's he has a fire extinguisher as well, but does not intend to start a fire! In fact I will email this to him, Charlie come in!
The Kinetic energy a 2000lb big Ford or Gm vehicle at say 40 MPH, probably surpasses some artillery shells! It was a company car yes?
The vehicle they were following was a match to the info they had, and going at a slow speed, weapons observed, IMO it should have been seat belts tight, swing wide, nail drivers door!
Windows open on passenger side of FBI vehicle, shoot from inside, driver and rear seat passenger exit. Advice to the shooters in FBI car, do not shoot the ones with FBI on their backs!
A friend of mine, for some 35 years (he can retire any time) works for a Police Dept. that has 870s and AR15s in the shop, he is the only one on the shift who books one of each out every day he works, the same two he has shot a bunch of rounds through. They can only ride in cases in the trunk.
He tells his Buddy's he has a fire extinguisher as well, but does not intend to start a fire! In fact I will email this to him, Charlie come in!
Shawn Dodson
Moderator
csmsss writes:
CARGUY2244 writes:
This entire argument is irrelevant. The purpose of ballistic gelatin testing is observe bullet performance (penetration, expansion, fragmentation, yaw) in a realistic "typical" soft tissue medium. All vital tissues are soft tissues.
CARGUY2244 writes:
I'm unaware anyone who's ever made such a claim. The closest I know of was a comment by John Hall, then SAIC FBI-FTU, who I paraphrase: "All else aside, Miami was an ammunition failure." Jerry Dove achieved a perfect hit but the bullet didn't penetrate deeply enough damage Platt's heart, which, given the bullet's path, would have substantially decreased it's ability to deliver blood.
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I must disagree. Yes, all vital tissues are soft tissues. But the human body isn't composed only of vital tissues. It is also composed of skin and muscle and bone, all of which may be between the bullet as it enters the body and the soft vital organs. All of these tissues have an effect in slowing the bullet, deflecting it from an otherwise predictable path, and altering its penetration/expansion properties. Further, even vital organs react differently from organ to organ - to direct trauma from the bullet, as well as to temporary trauma (cavitation, if you will). A lung will not react the same way to a gun shot wound that a kidney will, for example, yet a wound in either location can of course be fatal.
I don't disagree that ballistics gelatin is as good an objective simulacrum as we have for examining how bullets perform in soft tissue; however, it is still extremely imperfect when it comes to making ironclad predictions as to how a bullet will perform when it strikes a human being. There are just far too many other variables which enter the picture and which cannot be perfectly accounted for when designing a bullet.
If my "argument" (if you want to call it that) is so irrelevant, then why do bullet wounds, even from the same firearm firing the same cartridge, create such disparate effects from shooting to shooting?
Shawn Dodson
Moderator
csmsss writes:
Is lung tissue going to deflect a bullet from center punching the heart, as would have been the case with wound Dove inflicted on Platt? No. IMO, the the other factors you present are of little practical relevance.
Cheers!
Instead of paraphrasing MacPherson's explanation I'll post an extract which discusses the lack of practical differences between ordnance gelatin and typical soft tissues:
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).
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).
Is lung tissue going to deflect a bullet from center punching the heart, as would have been the case with wound Dove inflicted on Platt? No. IMO, the the other factors you present are of little practical relevance.
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.
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.
Cheers!
Shawn Dodson
Moderator
JohnKSa writes:
Odd Job writes:
I've seen bullets, both handgun and rifle, "deflected" in gelatin, caused by yaw or hydrodynamic effects of asymmetrical expansion.
Yes, it perforated the right biceps muscle (wound B in the autopsy report).
Odd Job writes:
I've seen bullets, both handgun and rifle, "deflected" in gelatin, caused by yaw or hydrodynamic effects of asymmetrical expansion.
I'm talking about significant deflection (probably would go out the gel block unexpectedly).
Here is an extreme example of what I mean:
The weapon was a handgun, ammunition and calibre unknown.
Skin breaches marked with paperclips, expected trajectory was somewhere along the red line, or in proximity thereof. Actual trajectory confirmed at surgery was yellow line (there was a liver injury).
No bony injury was found, no evidence of a bone strike.
Could you see such a radical change of trajectory in gel?
Here is an extreme example of what I mean:
The weapon was a handgun, ammunition and calibre unknown.
Skin breaches marked with paperclips, expected trajectory was somewhere along the red line, or in proximity thereof. Actual trajectory confirmed at surgery was yellow line (there was a liver injury).
No bony injury was found, no evidence of a bone strike.
Could you see such a radical change of trajectory in gel?
Shawn Dodson
Moderator
I have to ask, what kind of tissue could force a bullet to make a sudden 90-degree turn?
Was the subject's body pressing against a hard surface (e.g., lying down, leaning against a concrete wall, etc.)
A two dimensional xray and vague explanation is not enough information to discern what happened.
We need the full story.
Cheers!
Was the subject's body pressing against a hard surface (e.g., lying down, leaning against a concrete wall, etc.)
A two dimensional xray and vague explanation is not enough information to discern what happened.
We need the full story.
Cheers!
Shawn, the round didn't exit the abdominal cavity in the region of the change of trajectory. The only damage that was found in that region was a liver laceration (more like a groove actually) that was packed with SurgiSilk.
I photographed the man and his clothing, supervised or took the X-rays (I can't say which without digging up the case notes) and I accompanied the man to theatre and watched the surgery.
If I thought there was another reason for that deflection, I would offer it, but so far it goes down in my book as a soft tissue deflection. It isn't the only one I've seen, but it is one of the most bizarre.
I photographed the man and his clothing, supervised or took the X-rays (I can't say which without digging up the case notes) and I accompanied the man to theatre and watched the surgery.
If I thought there was another reason for that deflection, I would offer it, but so far it goes down in my book as a soft tissue deflection. It isn't the only one I've seen, but it is one of the most bizarre.
Shawn Dodson
Moderator
Well, dang it, dig out your notes. What tissues were involved?
Cartridge? Make? Bullet weight? What did the recovered bullet look like?
The FN P90 and 4.45x39mm yaw almost 90-degrees in gelatin and soft tissues. I doubt it was merely a "soft tissue" deflection - there's more involved.
Cartridge? Make? Bullet weight? What did the recovered bullet look like?
The FN P90 and 4.45x39mm yaw almost 90-degrees in gelatin and soft tissues. I doubt it was merely a "soft tissue" deflection - there's more involved.
Okay, I got the notes.
This was a male in his late twenties, shot once at near contact range. All he could say was that it was a handgun pressed close to his body, during a close quarters scuffle. He was wearing an unzipped all-weather jacket and a T-shirt at the time.
Only one shot was fired.
The round went through the T-shirt and breached his skin in the left upper quadrant of the abdomen, anteriorly. There was stippling of the skin in an oval distribution at the entrance site. The round exited at the lower right quadrant of the abdomen, anteriorly. There was a single exit wound.
The projectile did not breach the T-shirt at the exit site but there were four small holes in the fabric at the expected exit site in the fabric. I can't find any explanation for the four small holes in the T-shirt and the likelihood is that the projectile breached the skin, hit the inside of the T-shirt and dropped to the ground. No projectile was recovered. (Note: some of these patients keep the bullets in order to have them blessed by a Sangoma so that the gunshot injury does not cause impotence, financial ruin or undue infection. It is entirely possible that he picked up the bullet and pocketed it, or passed it to a relative before attending hospital).
He had a seated AP CXR and a supine AXR (not done by me). No opaque fragments were found. No bony injury was found.
At surgery there were two findings:
1) Hole in the left hemidiaphragm (which they sutured)
2) A groove or laceration to the liver anteriorly, left lobe. This groove was almost horizontal, a few inches long and was packed with SurgiSilk.
I took photographs during the surgery and watched the surgeons looking for damaged organs. Everything was fine except for the injuries above. No injury was found on the inside of the abdominal cavity and there was no skin breach anywhere in the right upper quadrant. The only damage found was two skin breaches, one hole in the left hemidiaphragm and one liver injury. I could not photograph the diaphragm injury but I did get pics of the liver injury. I couldn't get round to the patient's right to photograph that diaphragm injury (would have needed a really low angle shot from the lower right of the patient).
The only other intervention done was a chest drain, more as a precaution against a pneumothorax on the left.
The patient made a full recovery.
The only logical conclusion here is that the projectile made a course change in the right upper quadrant. Only the liver was damaged in that area, and there is no way a hard surface could contact the projectile to cause that change in direction.
I'll admit this is a very unusual and extreme example of this kind of deflection, but I have seen many others of a lesser magnitude. If these projectiles were immune to the affects of different tissue densities, we wouldn't be finding them tracking down tissue planes and 'off course' when comparing to the expected trajectory.
Of course there are variables that influence the interpretation of what that trajectory is, radiologically, but I doubt that any person working in the medical field is going to dispute the fact that projectiles from small arms have been seen or found in unexpected areas of the body without any bone strike having taken place.