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  #1  
Old 04-07-2012, 12:08 PM
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Fatal Wound Channel


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Good morning Forum,
As promised, I will have my paper done sometime this coming week. Several of the threads here within “Ballistics – Internals and External” have heated up since I proposed an equation for the ability of a bullet to create a fatal wound channel. I gave a preliminary report here earlier in the week.

I now want to update you on my progress. Again I used the drawings provided by Mr. Randy Wakeman Bullet Energy Transfer and Wounding Mechanisms . These drawings were from Dr. Martin L. Fackler Col. (USARet.) that he provided to Wound Ballistics, Ballistic Injury, Stopping Power, Gunshot Wounds . My point is to show a direct relationship of translational kinetic energy times sectional density times a factor of the bullets construction to predict a fatal wound channel.

Here is a truncated version of my final numbers using Pearson product-moment correlation coefficient
as a statistical tool:
1. Correlation of translational kinetic energy to the permanent wound channel .628 (High)
2. Correlation of translational kinetic energy to the temporary wound channel .734 (High)
3. Correlation of translational kinetic energy to the total wound channel .756 (High)
4. Correlation of translational kinetic energy to the penetration .362 (Medium)
5. Correlation of penetration to the sectional Density .682 (High)
6. Correlation of penetration to the momentum .347 (Medium)
7. Correlation of penetration to the IPF .640 (High)
8. Correlation of penetration to the TKO .147 (Low)
9. Correlation of momentum to the permanent wound channel .147 (Low)
10. Correlation of momentum to the permanent wound channel .224 (Low)
11. Correlation of momentum to the permanent wound channel .382 (Medium)
12. Correlation of IPF to the permanent wound channel .355 (Medium)
13. Correlation of IPF to the temporary wound channel .946 (very High)
14. Correlation of IPF to the total wound channel .615 (High)
15. Correlation of TKO to the permanent wound channel .098 (None)
16. Correlation of TKO to the temporary wound channel .020 (None)
17. Correlation of TKO to the total wound channel .044 (None)

Just so you know, the wound channel volumes were calculated by scaling. Thanks to Dr. Feckler he put a scale into his drawings. My Coefficient of Design values are from my book (2005) but I derived the values between 1996 and 2000. So there was no monkey business when I was running the numbers this last week. I didn't make the numbers fit my own self interest.

So I would say, my hypothesis still holds water.

For those who still don't understand what this has to do with hunting cartridges (handgun, black powder, shot gun, rifle and muzzle loaders), and harvesting game animals (from a 2 ˝ pound prieri dog to a 10,000 pound bull elephant), here's the bottom line.

You can compare two or more hunting cartridges regardless of how ridicules; e.g. a .257 Weatherby vs. a 45-120 Sharpe’s or .44 Remington Mag. Vs .30-30 Winchester. Furthermore, you can compare different bullets within the same cartridge having the same impact velocity: e.g. 180gr bullet; .30-'06 Springfield cartridge; Barnes TTSX to Berger 180VLD to Hornady A-Max to Sierra Gameking to Nosler AccuBond and on and on and on.

QUESTION: Can I use the “Image” button to post a PDF doc., will that work? I seem not to "attachment" rights. If not, how do I post may paper for all to see and critique?

Thanks again, Greg

P.S. No one has to buy my book. After I post my paper I'll post all Coefficient of Design values (including those derived after the book, like Berger hunting bullets). Also I have an empirical list of IPF values from game animals.

Last edited by mr glo; 04-08-2012 at 09:26 AM.
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Old 04-08-2012, 05:15 AM
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mr glo, I gotta hand it to you. You have turned what used to be an entertaining campfire-side chat subject in to one I will avoid at all costs in the future. :-)
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Old 04-08-2012, 01:59 PM
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OK, I'll bite...what is "IPF" ?

I will also reiterate my earlier assertion that any single formula which proposes to quantify terminal performance is doomed to failure. At best, these data can be used in a comparative analysis, but will not be universally successful in predicting how well an 85gr TTSX from a hot 6mm will kill, versus a hard-cast "heavy" from a 45-70. It is not surprising that no single formula can answer this "question", when there are at least 4 different interdependent values that must be taken into account.

I like the premises listed above, but would point out that even these data serve more to muddy the waters than clarify anything. I won't sit here and pick any or all of this apart, but I can think of convincing arguments to each of the correlation values in the table posted. You are to be commended for taking an exhaustive look into this long-standing and challenging question, but would you be willing to admit, at this point, that the final final is simply...

"it depends"?
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Old 04-08-2012, 03:00 PM
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Originally Posted by broom_jm View Post
OK, I'll bite...what is "IPF" ?

I will also reiterate my earlier assertion that any single formula which proposes to quantify terminal performance is doomed to failure. At best, these data can be used in a comparative analysis, but will not be universally successful in predicting how well an 85gr TTSX from a hot 6mm will kill, versus a hard-cast "heavy" from a 45-70. It is not surprising that no single formula can answer this "question", when there are at least 4 different interdependent values that must be taken into account.

I like the premises listed above, but would point out that even these data serve more to muddy the waters than clarify anything. I won't sit here and pick any or all of this apart, but I can think of convincing arguments to each of the correlation values in the table posted. You are to be commended for taking an exhaustive look into this long-standing and challenging question, but would you be willing to admit, at this point, that the final final is simply...

"it depends"?
Hi broom,
I don't have time to fully answer you. Easter services to night. As you have noticed I am profoundly dyslexic. Spelling and grammar on the fly ain't my strong suit.

Tomorrow I will run the numbers for your 6mm and .458 bullets to 500 yards in 50 yard increments. I don't know many folks that will try to take game with either cartridge (is a 244 H&H Mag hot enough [81.5gr H2O] ) at that distance. But it would be easier if you just give me an impact distance and game animal.

IPF is Translational kinetic energy times sectional density divided by a design factor for a bullet within a specific impact velocity range. Here is an example:

Design Type: Impact Velocity: Id.
core bonded 0 to 900fps .400
core bonded 900 to 1100fps .555
core bonded 1100 to 1400fps .741
core bonded 1400 to 2000fps .769
core bonded 2000 to 2900fps .800
core bonded 2900 to 3500fps .870

I am almost finished with my paper and answer. It should answer all your questions. If not that's why I'm going to put it out there for all of you.

Greg

P.S. Don't read anything into the id values because that appear to be in an ascending order. Trust me, it don't work that way when you properly apply the impact velocities.

Last edited by mr glo; 04-08-2012 at 05:00 PM.
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Old 04-08-2012, 06:51 PM
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A bullet strike is an inelastic collision, energy transforms into other forms of energy mostly thermal in this type of collision
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Old 04-08-2012, 07:06 PM
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A bullet strike is an inelastic collision, energy transforms into other forms of energy mostly thermal in this type of collision
3081ft-lbf = 1 calorie, what is your point?
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Old 04-08-2012, 07:45 PM
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Quote:
Originally Posted by mr glo View Post

IPF is Translational kinetic energy times sectional density divided by a design factor for a bullet within a specific impact velocity range. Here is an example:
OK, but what do the letters stand for? Is it part of your thesis, so you don't want to spoil the surprise?
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Old 04-08-2012, 08:55 PM
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mr glo,
You are not able to post an attachment until you have at least 25 posts. Read here for the details: http://www.shootersforum.com/beartoo...hnical-issues/

Some may want to read it, and maybe pick it apart, so prepare yourself for that.
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Last edited by Shawn Crea; 04-08-2012 at 08:58 PM.
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Old 04-09-2012, 05:33 AM
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Originally Posted by Shawn Crea View Post
mr glo,
You are not able to post an attachment until you have at least 25 posts. Read here for the details: Beartooth Board Operations & Technical Issues - Shooters Forum

Some may want to read it, and maybe pick it apart, so prepare yourself for that.
Thanks Shawn, I think I'm close to 25 posts.

Again thanks, I am ready for major push back. I have had this informal discord for several years now. I always try to be civil and informitive.

The biggest stumbling block or wall if you may, seems to be that the words “translational” and its root, “translate”. It seems that the physics and/or engineering communities feel they own the words and that the words are specific to thermodynamics (e.g ft-lbf translating to btu or calorie). Here at the forum I thing the knowledge base is a bit broader than physics and engineering.

Nothing could be further from the truth. See Mc Graw-Hill encyclopedia of Science and Technology, volume ice-lev, 9th Edition, Mc Graw-Hill, 2002, for kinetic energy, translational. Also see any dictionary.

Refdesk.com has this definition for "translational" - translation: Physics; Motion of a body in which every point of the body moves parallel to and the same distance as every other point of the body. I do not see thermodynamics anywhere in this definition.

Last edited by mr glo; 04-09-2012 at 05:36 AM.
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Old 04-09-2012, 05:56 AM
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OK, but what do the letters stand for? Is it part of your thesis, so you don't want to spoil the surprise?
No surprise broom, IPF means Impact Penetration Factor. It's a name. Just like Coefficient of Form (original name) or Form Factor (the common name). Sectional Density divided by Form Factor equals Ballistic Coefficient, which is another name.

IPF stands as a value because I don't use the coefficient of 12 to set the term equale to feet as is mathematically correct. Otherwise it would be a correct measurement for Fd divided by m/d^2 or Fm/d.

So why don't I correct the term? Because number or value would not "translate" well to hunting and shooting community.

As a note: I use words in their general first definitional meaning. I can and do use techno babel. But to a limited amount. Also I use Imperial units of measure from the English Engineering System not SI units of measure from the Absolute System; foot-pound force, ft-lbf and Fmdt not Newton meter, Nm and mdt respectively.

Last edited by mr glo; 04-09-2012 at 06:18 AM.
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Old 04-09-2012, 06:09 AM
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Quote:
Originally Posted by mr glo View Post
The biggest stumbling block or wall if you may, seems to be that the words “translational” and its root, “translate”. It seems that the physics and/or engineering communities feel they own the words and that the words are specific to thermodynamics (e.g ft-lbf translating to btu or calorie). Here at the forum I thing the knowledge base is a bit broader than physics and engineering.
Precise definitions of words in the sciences and engineering have a real purpose. The sloppy use of those words in general conversation causes confusion and misunderstandings. You say this work is part of a thesis - if you want to have credence as a professional, it is imperitave that you are precise in your communications in both your professional and popular writings. Good luck in your professional development.
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Old 04-09-2012, 06:48 AM
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OK, so IPF is your baby? Got it!

Specifically, the formula you have come up with seems targeted at quantifying how well a bullet will do at creating a temporary wound channel. Whether or not that was your intent or just a happy coincidence, I don't know. I also wonder if your formula takes into account all big-game hunting bullets, or is a simple derivative of earlier work with primarily pistol bullets, vis a vis, Dr. Fackler's work?

I have read Wakeman's paper before and find it humorous that he dismisses one formula (TKO) based primarily on whether or not the animals harvested while postulating the formula were harvested legally...as if that has some bearing on how effective the bullet was?

I don't dismiss Wakeman's conclusions in their entirety, but the man is an inveterate blow-hard who is incredibly opinionated. He presents his thoughts on the topic vociferously, but offers little in the way of original research, relying almost exclusively on regurgitation of Dr. Fackler's work. About the only thing Wakeman offers of any real import is the following quote:

"It goes to show that the wounding dynamic of a specific cartridge and projectile is impossible to properly define in terms of just energy, penetration, or shooting into dead newsprint, much less the inane TKO value."

And yet, the TKO value, in real life hunting conditions, particularly with medium and large-bore projectiles, is highly predictive of how effective a round will be. Again, there is no formula (no, not even yours) that can put a small diameter, limited mass projectile, traveling at a very high velocity, on the same graph with a large caliber, non-expanding projectile, flying through the air at half the speed. Both kill things quite well, at their intended ranges, but there is no single formula that can be used to explain why, exactly.

With all of that being said, I would be interested in reading your paper, UNLESS it is geared almost entirely toward gunshot wounds inflicted by pistol caliber rounds. If that is the case, such is not germane to the discussion at hand, anyway.
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Old 04-09-2012, 09:14 AM
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Originally Posted by broom_jm View Post
OK, so IPF is your baby? Got it!

Specifically, the formula you have come up with seems targeted at quantifying how well a bullet will do at creating a temporary wound channel. Whether or not that was your intent or just a happy coincidence, I don't know. I also wonder if your formula takes into account all big-game hunting bullets, or is a simple derivative of earlier work with primarily pistol bullets, vis a vis, Dr. Fackler's work?

I have read Wakeman's paper before and find it humorous that he dismisses one formula (TKO) based primarily on whether or not the animals harvested while postulating the formula were harvested legally...as if that has some bearing on how effective the bullet was?

I don't dismiss Wakeman's conclusions in their entirety, but the man is an inveterate blow-hard who is incredibly opinionated. He presents his thoughts on the topic vociferously, but offers little in the way of original research, relying almost exclusively on regurgitation of Dr. Fackler's work. About the only thing Wakeman offers of any real import is the following quote:

"It goes to show that the wounding dynamic of a specific cartridge and projectile is impossible to properly define in terms of just energy, penetration, or shooting into dead newsprint, much less the inane TKO value."

And yet, the TKO value, in real life hunting conditions, particularly with medium and large-bore projectiles, is highly predictive of how effective a round will be. Again, there is no formula (no, not even yours) that can put a small diameter, limited mass projectile, traveling at a very high velocity, on the same graph with a large caliber, non-expanding projectile, flying through the air at half the speed. Both kill things quite well, at their intended ranges, but there is no single formula that can be used to explain why, exactly.

With all of that being said, I would be interested in reading your paper, UNLESS it is geared almost entirely toward gunshot wounds inflicted by pistol caliber rounds. If that is the case, such is not germane to the discussion at hand, anyway.
Hi broom, I wish I had the command of the English language as you do. You write very much like my father.

My Dad was a senior staff engineer for Hughes Air Craft. Thanks to him I have the first photograph taken on the moon by the United States of America. Yeah he helped put a man on the moon. He was an engineer and publisher. For the programs he worked, nothing got to NASA or the Pentagon with his review or approval.

But I digress.

I completely agree with your assessment of Mr. R. Wakeman's paper. I can guaranty my “formula” will predict a fatal wound for any fur baring/big game animal. As I said, from prairie dogs to bull elephants. That fatal wound being a kill shots to the brain, cervical/thoracic spinal region, heart and lungs.

With no testing done that I have access to or appreciable records for wound channel volumes, I can't yet show a specifically calculated relationship of translational kinetic energy or IPF to a fatal wound. That is why this is still a hypothesis.

It is a hypothesis because it is based in proven science; remember, numbers first, experiments second. I did the number years ago. Now we have limited experiment to put my numbers too. Again the experiment is in real time, not a postmortem. A kill shot is a real time event. A postmortem is a postulation.

I'm not sure where you get this idea of hand gun bullets. I assure you, I have no allegiance to small fast bullets, light bullets, big heavy bullets, big slow bullets, lead bullets, copper alloy bullets, bonded bullets, duel cord bullets, partitioned bullets, lead shot, heat treated cast bullets, target bullets, fragmenting bullets or any other combination thereof.

However, IPF and transitional kinetic energy as understand them have nothing to do with arrows. That seems to be another issue of contention.

Thanks much for your open mind. I wish I had you writing this stuff. We would make a great team; your writing skills and my math skills.

Last edited by mr glo; 04-09-2012 at 09:18 AM.
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Old 04-09-2012, 10:22 AM
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You write better than most, and certainly sufficient to the task.

The most salient point from your previous entry is as follows: "A postmortem is a postulation." (Great word, btw!)

Per Merriam-Webster: Postulate - transitive verb - to assume or claim as true, existent, or necessary : depend upon or start from the postulate of

In other words, when we perform a postmortem examination of a big game animal that succumbed to the effects of a specific projectile (bullet) we must assume certain things to be true; the animal died as a result of the various wound types created by the impact of that projectile. Unfortunately, determining exactly what the bullet did, and why, is a very messy process, both literally and metaphorically.

Some bullets penetrate a short distance and go to pieces rather violently. Other bullets penetrate fully with little or no fragmentation, exiting the animal, such that an examination of the bullet is not possible. Since both kill very well, albeit in entirely different ways, I am curious as to how a single formula can allow for both types of effectiveness.

Arrows kill for the rather obvious reason that lacerating organs in the cardio-thoracic cavity causes massive hemorrhaging, which leads rather quickly to a drop in blood pressure and an insufficient supply of oxygenated blood to the brain. This causes the animal to slip into a coma in a surprisingly short period of time, which explains why archery equipment is a humane and effective means of harvesting big game animals.

I've done my share of technical writing (in the IT field) and would just as soon avoid more of it! This matter of why bullets perform the way they do is interesting to me, but I'd rather not be faced with the daunting task of writing it out for peer review. You have my sympathies!
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Old 04-09-2012, 12:25 PM
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Originally Posted by broom_jm View Post
OK, I'll bite...what is "IPF" ?

I will also reiterate my earlier assertion that any single formula which proposes to quantify terminal performance is doomed to failure. At best, these data can be used in a comparative analysis, but will not be universally successful in predicting how well an 85gr TTSX from a hot 6mm will kill, versus a hard-cast "heavy" from a 45-70. It is not surprising that no single formula can answer this "question", when there are at least 4 different interdependent values that must be taken into account.

I like the premises listed above, but would point out that even these data serve more to muddy the waters than clarify anything. I won't sit here and pick any or all of this apart, but I can think of convincing arguments to each of the correlation values in the table posted. You are to be commended for taking an exhaustive look into this long-standing and challenging question, but would you be willing to admit, at this point, that the final final is simply...

"it depends"?
Okay broom here you go!

Oh by the way, Barnes don't make an 85gr TTSX, but they do make an 80gr TTSX. I'll assume you meant 85gr TSX. In any event the TTSX and TSX bullets both have the same id value. These bullets are both truncated copper alloy bullets. The polycarbonate tip on the TTSX makes no appreciable difference in the disbursement of energy from this type of bullet (it dose when it comes to a jacketed lead core bullet).

I choose a 430gr hard cast .459 cal bullet for your .45-70. It is a 430gr Flat Nose Gas Check from Oregon Trails. I calculated the advertised bc to be .158. I estimated the muzzle velocity to be 2080ft/s from a Ruger #1.
I used the .244 H&H Mag for your 6mm Barnes TSX. I computed its muzzle velocity to be 3909ft/s using Load From A Disk ballistics software.

These are the minimum IPF for the game animals listed and those species of related size.
For the 6mm Bullet:
yds; ft/s; ft-lbf; IPF; Game Animal
M; 3909; 2885; N/A; N/A
50; 3730; 2629; N/A; N/A
100; 3559; 2391; 617; Harvest Elk (<600lb), American Bison, Leopard, African Thin skin (<100lb)
150; 3394; 2175; 561; and smaller game animals
200; 3236; 1977; 510; African Thin skin (<100lb)
250; 3084; 1796; 463; and smaller game animals
300; 2937; 1629; 437; Big Horn
350; 2795; 1475; 395; Deer (>150lb), African Thin skin (<50lb)
400; 2657; 1333; 357; and smaller game animal
450; 2524; 1205; 323; Mountain Goat
500; 2394; 1082; 290; Deer (<150lb), Pronghorn and smaller game animals

For the Hard Cast Bullet:
yds; ft/s; ft-lbf; IPF; Game Animal
M; 2080; 4132; N/A; N/A
50; 1840; 3233; 1086; Brown Bear, African Thin skin (<500lb),
100; 1620; 2506; 842; Trophy Elk (<600lb), Moose, African Thin skin (<250lb)
150; 1424; 1937; 651; Harvest Elk (<600lb), American Bison,
200; 1257; 1504; 617; Leopard
250; 1128; 1215; 497; African Thin skin (<100lb)
300; 1037; 1027; 660; Harvest Elk (<600lb), American Bison,
350; 970; 899; 578; and smaller game animals
400; 918; 805; 518; and smaller game animals
450; 873; 728; 468; and smaller game animals
500; 834; 664; 427; and smaller game animals

There is no typo when the IPF jumps up from 497 to 660 for the 40-75 hard cast bullet. The bullet is beginning to act like a solid at that impact velocity; 1037ft/s.
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Old 04-09-2012, 12:34 PM
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Originally Posted by broom_jm View Post
You write better than most, and certainly sufficient to the task.

The most salient point from your previous entry is as follows: "A postmortem is a postulation." (Great word, btw!)

Per Merriam-Webster: Postulate - transitive verb - to assume or claim as true, existent, or necessary : depend upon or start from the postulate of

In other words, when we perform a postmortem examination of a big game animal that succumbed to the effects of a specific projectile (bullet) we must assume certain things to be true; the animal died as a result of the various wound types created by the impact of that projectile. Unfortunately, determining exactly what the bullet did, and why, is a very messy process, both literally and metaphorically.

Some bullets penetrate a short distance and go to pieces rather violently. Other bullets penetrate fully with little or no fragmentation, exiting the animal, such that an examination of the bullet is not possible. Since both kill very well, albeit in entirely different ways, I am curious as to how a single formula can allow for both types of effectiveness.

Arrows kill for the rather obvious reason that lacerating organs in the cardio-thoracic cavity causes massive hemorrhaging, which leads rather quickly to a drop in blood pressure and an insufficient supply of oxygenated blood to the brain. This causes the animal to slip into a coma in a surprisingly short period of time, which explains why archery equipment is a humane and effective means of harvesting big game animals.

I've done my share of technical writing (in the IT field) and would just as soon avoid more of it! This matter of why bullets perform the way they do is interesting to me, but I'd rather not be faced with the daunting task of writing it out for peer review. You have my sympathies!
You now have a very full grasp of this whole issue of fatal wounds.

Because my formula takes into account bullet behavior (e.g. liquid, fragmentation, partial expansion, full expansion, solid, etc...) at differing impacts as well as sectional density, the IPF will express its self for blow-ups, short penetration and bullet exiting.

Thanks for the kind words.
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Old 04-09-2012, 02:32 PM
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Originally Posted by mr glo View Post
Okay broom here you go!

Oh by the way, Barnes don't make an 85gr TTSX, but they do make an 80gr TTSX. I'll assume you meant 85gr TSX. In any event the TTSX and TSX bullets both have the same id value. These bullets are both truncated copper alloy bullets. The polycarbonate tip on the TTSX makes no appreciable difference in the disbursement of energy from this type of bullet (it dose when it comes to a jacketed lead core bullet).

I choose a 430gr hard cast .459 cal bullet for your .45-70. It is a 430gr Flat Nose Gas Check from Oregon Trails. I calculated the advertised bc to be .158. I estimated the muzzle velocity to be 2080ft/s from a Ruger #1.
I used the .244 H&H Mag for your 6mm Barnes TSX. I computed its muzzle velocity to be 3909ft/s using Load From A Disk ballistics software.

These are the minimum IPF for the game animals listed and those species of related size.
For the 6mm Bullet:
yds; ft/s; ft-lbf; IPF; Game Animal
M; 3909; 2885; N/A; N/A
50; 3730; 2629; N/A; N/A
100; 3559; 2391; 617; Harvest Elk (<600lb), American Bison, Leopard, African Thin skin (<100lb)
150; 3394; 2175; 561; and smaller game animals
200; 3236; 1977; 510; African Thin skin (<100lb)
250; 3084; 1796; 463; and smaller game animals
300; 2937; 1629; 437; Big Horn
350; 2795; 1475; 395; Deer (>150lb), African Thin skin (<50lb)
400; 2657; 1333; 357; and smaller game animal
450; 2524; 1205; 323; Mountain Goat
500; 2394; 1082; 290; Deer (<150lb), Pronghorn and smaller game animals

For the Hard Cast Bullet:
yds; ft/s; ft-lbf; IPF; Game Animal
M; 2080; 4132; N/A; N/A
50; 1840; 3233; 1086; Brown Bear, African Thin skin (<500lb),
100; 1620; 2506; 842; Trophy Elk (<600lb), Moose, African Thin skin (<250lb)
150; 1424; 1937; 651; Harvest Elk (<600lb), American Bison,
200; 1257; 1504; 617; Leopard
250; 1128; 1215; 497; African Thin skin (<100lb)
300; 1037; 1027; 660; Harvest Elk (<600lb), American Bison,
350; 970; 899; 578; and smaller game animals
400; 918; 805; 518; and smaller game animals
450; 873; 728; 468; and smaller game animals
500; 834; 664; 427; and smaller game animals

There is no typo when the IPF jumps up from 497 to 660 for the 40-75 hard cast bullet. The bullet is beginning to act like a solid at that impact velocity; 1037ft/s.
Two things jump out at me, actually. If I'm reading this correctly, the IPF for the 6mm bullet at 100 yards is 617, which is also the exact same number for the 45 caliber bullet at 200 yards. Are we to conclude from this that the 244H&H, with an 85gr TSX at 100 yards would kill game animals in much the same way as the 45/70 with a 430gr hard-cast bullet at 200 yards?

Also, is it your assertion that the 45 bullet is NOT behaving as a solid at ranges less than 300 yards?

If that 45 caliber bullet were fired from a stoutly-loaded 45 Colt, at a MV of say 900fps, the IPF would be ~515 and it would be suitable for game smaller than a cow elk? I'm intrigued, but still far too many questions.

Last edited by broom_jm; 04-09-2012 at 02:36 PM.
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Old 04-09-2012, 03:54 PM
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Originally Posted by broom_jm View Post
Two things jump out at me, actually. If I'm reading this correctly, the IPF for the 6mm bullet at 100 yards is 617, which is also the exact same number for the 45 caliber bullet at 200 yards. Are we to conclude from this that the 244H&H, with an 85gr TSX at 100 yards would kill game animals in much the same way as the 45/70 with a 430gr hard-cast bullet at 200 yards?

Also, is it your assertion that the 45 bullet is NOT behaving as a solid at ranges less than 300 yards?

If that 45 caliber bullet were fired from a stoutly-loaded 45 Colt, at a MV of say 900fps, the IPF would be ~515 and it would be suitable for game smaller than a cow elk? I'm intrigued, but still far too many questions.
Okay to answer paragraph 1. If you are inferring that wound channel would look the same, then the answer is no. Meaning the .45 cal bullet and 6mm bullet would create the same shape wound chanel. I hypothesize that the .45 cal bullet might penetrate deeper and have a more narrow temporary wound channel.

If my hypothesis is correct both bullets will create near the same temporary wound channel volume. This would translate into the same blunt force trauma; tissue damage, blood loss, blood pressure loss, shock and immanent death.

Again a postmortem would not show this and the technician would be making a postulation.

Paragraph 2. It is my assertion that an impact less than 50 yards, the bullet will fail by virtue of liquid impact. That between 50 and 300 yards there will discernible distortion in the bullet. That between 300 and around 700 yards there will be little distortion of the bullet and 700 yards and beyond there will be no discernible distortion in the bullet; a solid.

Paragraph 3. No, I have 579 IPF for a minimum Harvestable Elk. However, a small Cow elk may be within that range of 518. I may have to add some IPF values to be more reflective of Elk size. A calf elk during combination season is defiantly a harvestable elk but certainly takeable with a whole lot less than a 579 IPF. I would think a calf is about the size of a Big Horn ram.

A very good challenge broom. Keep it up and keep me honest. Given enough information I should be able to eventuality give exact IPF values for any animal weight and toughness. I should think Greenhill's equation for F = ma would suffice if I had the experimental data.
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Old 04-09-2012, 04:00 PM
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Do I understand correctly that one of the most important variables in this formula is derived from measurements of the penetration of various bullets in ballistic gelatin?
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Old 04-09-2012, 05:53 PM
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I wish I had the time to have a full understanding of your hypothesis and the comments of broom. So with that caveat I would like to ask a question that I think is a natural extension of broom's question and Glo's answer.

It seems to me that a larger bullet might at some point make a larger wound channel that does not penetrate deep enough to cause enough damage to the animals vital organs. Yet a smaller caliber say a 17 hornet might have a very small wound channel but go into the animal far enough to say punch a hole in its heart which I would think in all cases is a fatal wound.

what comes to mind is something that happened to me when I was still in grade school. I went to point at another student with a pencil. I had the point toward my hand and bumped the eraser into my desk. It put a pretty deep hole in my hand and the bits of graphite are still visible in my hand to this day. Now if I had the pencil was held the other way the force would have been the same but the eraser would have been large enough that it would not be able to penetrate my hand and I would not have my first self inflicted tattoo.
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