Users Currently Browsing This Topic:
0 Members

Author Topic: An Interesting Article Regarding Bullet Deformation  (Read 1737 times)

Online Mitch Todd

  • Hero Member
  • *****
  • Posts: 907
An Interesting Article Regarding Bullet Deformation
« on: August 10, 2021, 04:25:20 AM »
Advertisement
It's keyed towards the hollow point crowd, but it still has some value for assassination researchers. Most apropos to CE399 is the following quote from the second paragraph:

   "For bullets to deform, they need to have an impact velocity that’s capable of initiating the process.
    This will vary from bullet to bullet but generally speaking, a mono-metal bullet needs to impact at
    around 1800 fps, while some bonded bullets can start to deform on impact at around 1600 fps, and
    jacketed lead-core bullets can often start the process with impact velocities as low as 1400 fps. But
    we’re only talking about minimum deformation."

Compare this to Sturdivan's testimony to the HSCA.

https://www.fieldandstream.com/hunting/expanding-bullets/

JFK Assassination Forum

An Interesting Article Regarding Bullet Deformation
« on: August 10, 2021, 04:25:20 AM »


Offline Joe Elliott

  • Hero Member
  • *****
  • Posts: 1656
Re: An Interesting Article Regarding Bullet Deformation
« Reply #1 on: August 13, 2021, 03:42:37 AM »

It's keyed towards the hollow point crowd, but it still has some value for assassination researchers. Most apropos to CE399 is the following quote from the second paragraph:

   "For bullets to deform, they need to have an impact velocity that’s capable of initiating the process.
    This will vary from bullet to bullet but generally speaking, a mono-metal bullet needs to impact at
    around 1800 fps, while some bonded bullets can start to deform on impact at around 1600 fps, and
    jacketed lead-core bullets can often start the process with impact velocities as low as 1400 fps. But
    we’re only talking about minimum deformation."

Compare this to Sturdivan's testimony to the HSCA.

https://www.fieldandstream.com/hunting/expanding-bullets/

I think Sturdivan’s testimony to the HSCA is pretty similar to what he was saying years later in his book “The JFK Myths”.

In the testimony:

https://www.history-matters.com/archive/jfk/hsca/reportvols/vol1/pdf/HSCA_Vol1_0908_3_Sturdivan.pdf

He estimates the bullet struck Connally at around 1,700 feet per second, or a little less. And lost about 400 fps, exiting Connally’s torso between 1,100 and 1,300 fps. From this we can infer that the bullet was moving between 1,700 fps and 1,100 fps per second when it first struck Connally’s rib.

This is not vastly different than his estimate made ten years later in his book, where he estimated the bullet struck Connally’s rib at 1,400 fps.

Of course, in science, it is common for opinions to change in light of better experiments, or more data. The CDC has been criticized for first saying that masks won’t help, then masks help protect others but not the wearer of the mask. And then said it helps both the wearer and those around them. And the CDC has been criticized for waffling, not giving a consistent message. But this is common in science. Scientific opinion is commonly in flux and it takes awhile for a strong consensus to from, particularly in the earlier parts of an investigation. And, in any case, it’s not clear to me that Sturdivan’s opinion on the velocity of the bullet changed that much between the time he testified before the HSCA in the mid 1990’s and writing his book ten years later. In the 1990’s, he had a wide range of his estimate of the bullet’s velocity when it first struck the rib. Later experiments allowed him to make a narrower estimate, with a much smaller upper and lower limit range for the velocity.

Online Andrew Mason

  • Hero Member
  • *****
  • Posts: 1244
    • SPMLaw
Re: An Interesting Article Regarding Bullet Deformation
« Reply #2 on: August 14, 2021, 08:51:44 PM »
I think Sturdivan’s testimony to the HSCA is pretty similar to what he was saying years later in his book “The JFK Myths”.

In the testimony:

https://www.history-matters.com/archive/jfk/hsca/reportvols/vol1/pdf/HSCA_Vol1_0908_3_Sturdivan.pdf

He estimates the bullet struck Connally at around 1,700 feet per second, or a little less. And lost about 400 fps, exiting Connally’s torso between 1,100 and 1,300 fps. From this we can infer that the bullet was moving between 1,700 fps and 1,100 fps per second when it first struck Connally’s rib.

This is not vastly different than his estimate made ten years later in his book, where he estimated the bullet struck Connally’s rib at 1,400 fps.

Sturdivan assumed the bullet that struck JBC had passed through JFK.  But it had to also have enough energy to do the damage that JBC experienced to his torso and wrist.  His estimate of the speed on striking JBC in the back at 1,700 fps means that the bullet had (17/20)^2 =72% of the energy that it had before striking JFK. This is needed to explain the fact that there was more energy lost due to the damage to JBC than to JFK.

But this posed a problem for Sturdivan because this meant that the bullet striking  bone at 1700 fps should have deformed significantly. So he lowers the estimate to 1400 fps when striking bone. But that means that the bullet had lost more than half its energy (14/20)^2 = 49% in passing through JFK.  He never really explains how that could be, since there was much less damage to JFK than to JBC. 

But even 1400 fps is not low enough to avoid damage to the bullet if, as is suggested, it did not strike nose-on.  Sturdivan testified to the HSCA (3 HSCA 396):
  • "If it strikes bone, which is twice as dense [as water], then it would begin to deform nose on at approximately 1,400 feet per second. If the bullet turns sideways, which is a weaker orientation, it will deform down to around 1,000 feet per second."
There was, of course, no damage to CE399's nose.  The base had been pushed in on one side.  According to Sturdivan, that would begin to occur at 1,000 fps.   A 2000 fps bullet striking JFK, passing through his neck exiting his throat and then going on to strike JBC's rib at 1000 fps means it lost 75% of its energy in passing through JFK's neck.  So, what Sturdivan is actually saying is that the bullet lost three quarters of its energy in passing through JFK yet did most of its damage with the quarter that it had left.  That makes absolutely no sense.


Quote
Of course, in science, it is common for opinions to change in light of better experiments, or more data. The CDC has been criticized for first saying that masks won’t help, then masks help protect others but not the wearer of the mask. And then said it helps both the wearer and those around them. And the CDC has been criticized for waffling, not giving a consistent message. But this is common in science. Scientific opinion is commonly in flux and it takes awhile for a strong consensus to from, particularly in the earlier parts of an investigation. And, in any case, it’s not clear to me that Sturdivan’s opinion on the velocity of the bullet changed that much between the time he testified before the HSCA in the mid 1990’s and writing his book ten years later. In the 1990’s, he had a wide range of his estimate of the bullet’s velocity when it first struck the rib. Later experiments allowed him to make a narrower estimate, with a much smaller upper and lower limit range for the velocity.
The analogy to the CDC and its Covid advice is a bit of a stretch. The CDC was going by the knowledge it had based on transmissibility of similar viruses.  Sturdivan  was simply applying the laws of physics. The laws of physics did not change in those 10 years. There were no new experiments that Sturdivan based his "revised" opinion on.
« Last Edit: August 17, 2021, 10:46:23 PM by Andrew Mason »

JFK Assassination Forum

Re: An Interesting Article Regarding Bullet Deformation
« Reply #2 on: August 14, 2021, 08:51:44 PM »


Offline Joe Elliott

  • Hero Member
  • *****
  • Posts: 1656
Re: An Interesting Article Regarding Bullet Deformation
« Reply #3 on: August 26, 2021, 03:18:34 AM »
Sturdivan assumed the bullet that struck JBC had passed through JFK.  But it had to also have enough energy to do the damage that JBC experienced to his torso and wrist.  His estimate of the speed on striking JBC in the back at 1,700 fps means that the bullet had (17/20)^2 =72% of the energy that it had before striking JFK. This is needed to explain the fact that there was more energy lost due to the damage to JBC than to JFK.

But this posed a problem for Sturdivan because this meant that the bullet striking  bone at 1700 fps should have deformed significantly. So he lowers the estimate to 1400 fps when striking bone. But that means that the bullet had lost more than half its energy (14/20)^2 = 49% in passing through JFK.  He never really explains how that could be, since there was much less damage to JFK than to JBC. 

But even 1400 fps is not low enough to avoid damage to the bullet if, as is suggested, it did not strike nose-on.  Sturdivan testified to the HSCA (3 HSCA 396):
  • "If it strikes bone, which is twice as dense [as water], then it would begin to deform nose on at approximately 1,400 feet per second. If the bullet turns sideways, which is a weaker orientation, it will deform down to around 1,000 feet per second."
There was, of course, no damage to CE399's nose.  The base had been pushed in on one side.  According to Sturdivan, that would begin to occur at 1,000 fps.   A 2000 fps bullet striking JFK, passing through his neck exiting his throat and then going on to strike JBC's rib at 1000 fps means it lost 75% of its energy in passing through JFK's neck.  So, what Sturdivan is actually saying is that the bullet lost three quarters of its energy in passing through JFK yet did most of its damage with the quarter that it had left.  That makes absolutely no sense.


From the book, “The JFK Myths” by Larry Sturdivan:

Page 144, Table III, Probable Velocity and Orientation of CE 399 at Various Points Along Its Trajectory:

Impact on Kennedy’s Neck:   2015 f/s
Impact on Connally’s Back:   1830 f/s
Impact at start of rib:   1450 f/s
Impact at end of rib:   800 f/s
Impact on start of Connally’s Wrist:   500 f/s
Impact on start of Connally’s Thigh:   135 f/s

So, I have made a table showing in each column:
Column 1: Location along the wound tracks.
Column2: Ratio of distance left to travel
Column 3: Ratio of velocity to initial velocity at striking the neck
Column 4: Ratio of kinetic energy to initial kinetic energy

The first column, with digits 0 through 9 represent:

Location 0: Back of JFK’s neck
Location 1: Front of JFK’s neck

Location 2: Back of Connally’s back
Location 3: Start of rib
Location 4: End of rib
Location 5: Front of Connally’s torso

Location 6: Front of Connally’s wrist
Location 7: End of Connally’s wrist
Location 8: Start of Connally’s thigh
Location 9: Deepest penetration of Connally’s thigh

And here is the table:

0   1.00   1.00   1.00
1   0.71   0.91   0.82

2   0.71   0.91   0.82
3   0.43   0.72   0.52
4   0.22   0.40   0.16
5   0.16   0.25   0.06

6   0.16   0.25   0.06
7   0.06   0.07   0.00

8   0.06   0.07   0.00
9   0.00   0.00   0.00

This table is based on Mr. Sturdivan and my estimates of the length of the wound path within the bodies:

JFK’s neck was 14 cm wide (Mr. Sturdivan, Appendix B, Retardation in Tissue, page 270, 13.5 to 14.5 cm).
Connally’s torso was 27 cm wide (Mr. Sturdivan, Appendix B, Retardation in Tissue, page 270, 25 to 30 cm).
Connally’s wrist was 5 cm wide (my estimate)
Connally’s thigh was 3 cm long (my estimate, assuming the bullet penetrated about the length to the bullet)

I also estimate that within Connally’s torso, the bullet travelled about 14 cm before it struck the rib. Then it took out 10 cm of rib, then travelled another 3 cm through soft flesh before exiting the front of the torso. I think this is reasonable. Why wouldn’t the bullet hit a rib within the first 5 cm? Because the bullet struck near the right armpit and would have missed the ribs altogether, if it was travelling straight ahead. But, because it was angling inward, it just managed to strike a rib, taking out 10 cm of it.

I use nothing but numbers in my table so that the columns line up roughly.

I used the numbers from Mr. Sturdivan’s table. I assume there is no change in the velocity of the bullet while it is moving through the air, between JFK’s neck and Connally’s back, between Connally’s torso and his wrist, and between Connally’s wrist and his thigh, which would be pretty accurate since the distance travelled through the air is so short.

At the time the bullet struck JFK’s back of the neck, it was moving at 2015 f/s. I consider this to be 100 % of its initial speed, not the muzzle velocity but its speed at the time it first hit JFK.
At the time the bullet struck Connally’s back, it was moving at 1830 f/s, or with 91 % of it’s speed and 82 % of its energy.

I draw your attention to “Line 3” of my table. At the time the bullet struck Connally’s rib, it was moving at 1450 f/s or with 72 % of it’s speed and 52 % of its energy.

I see nothing unbelievable about the bullet, with about 43 % through its journey through flesh left to travel, would have about 72 % of its velocity and 52 % of its kinetic energy. This sounds about right.

The biggest thing that might raise an eyebrow, is that Mr. Sturdivan’s estimate that the 14 cm of JFK’s neck caused the bullet to lose 9 % of its velocity and 18 % of its kinetic energy. While the 27 cm of Connally’s torso caused the bullet to lose 66 % of its velocity and 76 % of its kinetic energy. But there are three reasons for this:

1. The bullet was travelling straight on through JFK’s neck, while travelling sideways through Connally. This would slow down the bullet up to 6 times as much, since the bullet could have up to 6 times as much cross-section, as it travelled through the torso.
The evidence that the bullet was travelling ‘sideways’ are:
a. ballistic tests show that a block of ballistic gel, about 6 inches wide, usually gets a bullet to start tumbling, not through the ballistic block but through the air immediately after it exits the block.
b. Connally did not have a circular entrance wound but an elongated wound.
c. CE 399 had damage not to the nose but to its side, consistent with it travelling sideways when it struck a rib.
All of which is consistent with the same scenario, the bullet travelling sideways through Connally’s torso and not point first as it did through JFK’s neck.

2. The bullet travelled through 10 cm of bone, which is twice as dense as soft tissue. This would have slowed the bullet more while travelling through the torso.

3. Human skin is very thin, about a tenth of an inch thick. But it is very tough and I recall retards the speed of a bullet a good amount. I have read that a tenth of an inch of skin retards the bullet as much as two inches of soft tissue. So, hitting the back, going through a coat, a shirt, possibly an undershirt and then skin, all while turned sideways, would slow the bullet a significant amount, even before it started to travel through the soft tissue of the torso.

Because of these three factors, the bullet was travelling faster when it first struck the rib, than one might expect, with 43 % of it’s journey left to travel, but still with 72 % of its velocity. But now, hitting significant bone for the first time, its rate of deceleration was about to increase dramatically.

And, of course, other ballistic experts, like Michael Haag and Luke Haag, find the Single Bullet Theory to be quite plausible. It is only laymen who do not find it plausible. In all the world, no ballistic expert, who set up and participate in real world ballistic experiments, like Larry Sturdivan, Michael Haag and Luke Haag, have a different opinion. At least none that I have ever hear of.

The analogy to the CDC and its Covid advice is a bit of a stretch. The CDC was going by the knowledge it had based on transmissibility of similar viruses.  Sturdivan  was simply applying the laws of physics. The laws of physics did not change in those 10 years. There were no new experiments that Sturdivan based his "revised" opinion on.

I’m not so certain there were no new experiments. Mr. Sturdivan still continued working at the at the Chemical Systems Laboratory, the Edgewood area of Aberdeen Proving Ground, Md. Where ballistic experiments still continued. They made have made new observations that would cause him to refine his estimates. Perhaps from new and improved ballistic gel. Perhaps from better models of bone. Perhaps from better simulations of skin and or clothes. Or other factors.

Even with no new experiments, thinking about the effects of bone, skin, clothes, the amount of yaw and other factors might cause one to adjust one’s estimate over a period of 10 years. All these estimates of the velocities of the bullets are estimates based on Mr. Sturdivan’s experiments and calculations, not observed scientific facts established by measurements from the Zapruder film and so now set in concrete.

Aha, these estimates are based on an opinion, not fact, I can hear others say. Yes. That is true. It is impossible to get these measurements from the Zapruder film or any other piece of evidence. So ‘opinion’ is the best we can reasonably expect to get. Not based on observing the speed of the bullet as it travelled through JFK and Connally, which is impossible with opaque bodies and at 18 frames per second. But we have the opinion of a ballistic expert, who has years of experiments participating in ballistic experiments, even using Carcano rifles. So, this opinion is as good as we can reasonably expect. And other ballistic experts do not seem to disagree with him.

Astronomers estimate of the distance to various stars have varied over time and will continue to do so. For instance, the distance to Arcturus, the fourth brightest star in the night sky, in 1933 was estimated to be 40 light years away. The current estimate is 36.7 light years. Measuring the distance to stars is seemingly straight forward because one can do so with basic geometry, using parallax shifts as the apparent position changes over the course of a year. And this work to estimate the distance to Arcturus and other stars had, by 1933, been going on for many decades. But these variations in estimates are not evidence of bad science but are to be expected as more information is learned over time.
« Last Edit: August 26, 2021, 05:10:08 PM by Joe Elliott »