Predictive tests in water

[Glock17JHP]

The chronograph used to obtain the test data (impact velocity) has been validated against a Lab Radar Doppler unit on numerous occasions and once—just recently—against a Garmin Xero C1: it has always demonstrated ±0.75% agreement with the other units. I have no reason to distrust the reading that the chronograph provided in this particular test.

I would reject this load for my usage if that velocity is correct.

[Glock17JHP]

I have a Detonics Combat Master .45 ACP, which has a 3.5-inch barrel and is designed for standard velocity (830ish fps) 230 grain FMJ ammunition. I want to select a hollowpoint that will expand and also is as close as possible in bullet shape, weight and velocity to this standard ammunition. At this point, it's down to Speer Gold Dot Short Barrel 230 grain (23975GD) @820 fps in a 4-inch barrel, and Federal HST 230 grain (P45HST2) @890 fps in a 5-inch barrel. I am leaning toward the Federal HST.

[Ghost Dog]

I have a Detonics Combat Master .45 ACP, which has a 3.5-inch barrel and is designed for standard velocity (830ish fps) 230 grain FMJ ammunition. I want to select a hollowpoint that will expand and also is as close as possible in bullet shape, weight and velocity to this standard ammunition. At this point, it's down to Speer Gold Dot Short Barrel 230 grain (23975GD) @820 fps in a 4-inch barrel, and Federal HST 230 grain (P45HST2) @890 fps in a 5-inch barrel. I am leaning toward the Federal HST.

Not sure if you're basing just on Terminal performance or if you have already function checked...

Reliability, especially w something so old short and chopped is paramount...

While hst is my choice especially from so short a barrel...if those 2 aren't thoroughly reliable I'd try 185 Golden Saber for nose profile and ogive discussed in another thread and because such a short barrel just my 2 cents

[Ghost Dog]

Can you please help in simple Lay terms?

Is the wound volume simply Volume of a Cylinder by Penetration and Expansion numbers? Or is there some variable modifying off that or in the equation? I don't have a device handy to check right now. If different is there a simple formula to figure this out one can use or it's simple Volume of a cylinder?

While adequate Penetration desired being met then Expansion therefore Would Volume seems the most important and reliable every time;
It seems that velocity and ME are all but ignored nowadays, however, I'm curious if E15 is also ignored now and if so why?

It would seem Pen/Exp/Would Volume are the most important and reliable but E15 would then be wanted as sometimes but not always may lead to higher psychological reaction (given a snippet of what Dr Gokor wrote theoretically on .357 sig not only louder bang and perhaps flash, but I'm wondering if e15 may indeed matter?)

Also, didn't Secret Service do some study going w fast 9mm then 357 sig? Has anyone ever had access to this?

And while most that old thinking under appreciating the most important metrics of Pen/Exp/Wound Volume perhaps E15 is that extra thing not being considered?

Or has that been totally disregarded now and if so why?

Certainly .357mag/Sig seemed to have had quicker changing of behavior in bad guys than similar 9mm close equivalent JHPs/bullet weights and yet they shouldn't on paper when ignoring velocity/ME/E15.
Bigger bullet more wound volume is every time but is e15 the other metric being ignored?

Typing on small cell phone I hope my questions make some sense.

[Ghost Dog]

Is there a simple way to plug and play figure out the E15 for each load tested or if you have Organic Gel Data? Please explain how to do that I find you including that metric interesting and wonder what readings would discuss this?

[Glock17JHP]

Reliability, especially w something so old short and chopped is paramount...

My Detonics Combat Master functions flawlessly with standard 230 grain FMJ. So, it should be fine with any 230 grain JHP that has a good bullet shape and is close to 830 fps (or slightly higher) in a 5-inch barrel. Since I trust the Federal HST standard velocity load, expansion at a lower velocity is my main concern. Trying currently to estimate velocity from my 3.5-inch barrel based on 890 fps from a 5-inch barrel.

Maybe I to just need to do some testing...

[Half Moon]

My Detonics Combat Master functions flawlessly with standard 230 grain FMJ. So, it should be fine with any 230 grain JHP that has a good bullet shape and is close to 830 fps (or slightly higher) in a 5-inch barrel. Since I trust the Federal HST standard velocity load, expansion at a lower velocity is my main concern. Trying currently to estimate velocity from my 3.5-inch barrel based on 890 fps from a 5-inch barrel.

Maybe I to just need to do some testing...

FWIW, might help you get in the ballpark:

http://ballisticsbytheinch.com/45auto.html

http://ballisticsbytheinch.com/45auto2.html

Testing would be best though. A lot of variables that can cause variation model to model.

[Ghost Dog]

My Detonics Combat Master functions flawlessly with standard 230 grain FMJ. So, it should be fine with any 230 grain JHP that has a good bullet shape and is close to 830 fps (or slightly higher) in a 5-inch barrel. Since I trust the Federal HST standard velocity load, expansion at a lower velocity is my main concern. Trying currently to estimate velocity from my 3.5-inch barrel based on 890 fps from a 5-inch barrel.

Maybe I to just need to do some testing...

feeding reliability is by far the bigger concern for that.

In Organic Gel, I've seen 45 HST expand as low as 730fps from Revolvers, and often in 3.3" tests as well.

Again, known JHP hollow point shape and ogive for reliable feeding in finicky 1911's is Golden Saber. Since only a 3.5", 185 gr recommended for most reliable expansion.

If you have a bunch of HST function check...if not going to check a ton, then I strongly suggest trying 185 Golden Sabers...you may find the recoil less as well which nice for that small Detonics. There is also 185+p if wanted, or 185 bonded if desired though less expansion

FBI data
45 ACP 185 grain Remington Golden Saber JHP, 3/21/94:

Test Gun Barrel Length Velocity
Bare Gelatin

Clothed Gelatin

Penetration Expansion Penetration Expansion
S&W M645

5" 1037 fps BARE 14.40" 0.72" CLOTHED15.95" 0.68"

In 17ish% less Dense Clear Ballistics
You can see 185s still expand in 3.64" Kahr in Lucky Gunner Labs

[the Schwartz]

Can you please help in simple Lay terms?

I'll do the best that I can.

Is the wound volume simply Volume of a Cylinder by Penetration and Expansion numbers? Or is there some variable modifying off that or in the equation? I don't have a device handy to check right now. If different is there a simple formula to figure this out one can use or it's simple Volume of a cylinder?

Predicted cavity volume is computed by multiplying the square of the expanded bullet's cross-sectional radius, r², times π (3.1415927), times the length, L, of the permanent cavity, times a projectile-specific configuration factor, Φ, or V = π·r²·L·Φ

While adequate Penetration desired being met then Expansion therefore Would Volume seems the most important and reliable every time;
It seems that velocity and ME are all but ignored nowadays, however, I'm curious if E15 is also ignored now and if so why?

It would seem Pen/Exp/Would Volume are the most important and reliable but E15 would then be wanted as sometimes but not always may lead to higher psychological reaction (given a snippet of what Dr Gokor wrote theoretically on .357 sig not only louder bang and perhaps flash, but I'm wondering if e15 may indeed matter?)

ΔE₁₅ is the amount of kinetic energy that a given projectile expends as it traverses a penetration depth of 1 centimeter to 15 centimeters through soft tissue or 10% ordnance gelatin test medium. The ΔE₁₅ parameter (in later research referred to as EKE or expected kinetic energy) is still in use by the US military today in the ballistic insult subroutine contained within the ORCA/MUVES-S2 SLV software that has been used successfully to match the capability of our small arms munitions to those of our adversaries' munitions over the last 50+ years. The ΔE₁₅ parameter is still relevant and not being ignored.

Due to technical misunderstanding and confusion, some researchers have chosen to ignore or discount the use of the ΔE₁₅ (or EKE) parameter mistaking it as a direct causal mechanism of tissue damage and incapacitation rather than as a correlative factor. If you wish to read the technical paper in which the ΔE₁₅/EKE parameter is correctly discussed, I would refer you to, A Mathematical Model for Assessing Weapons Effects From Gelatin Penetration by Spheres (AD-770352); Sturdivan, LM; Edgewood Arsenal, SAREA-BL-BS, Aberdeen Proving Ground, MD, 21010, September, 1973.

Here is a very brief excerpt from that source explaining the concept in simple terms:

''The ideal evaluative procedure is one in which the gelatin penetration/retardation performance of a projectile could be predicted from its physical characteristics. Conversely, the same models which allow prediction of performance could be used to design projectiles possessing the desired terminal, soft-target effects within the constraints placed on the weapon system. An integral part of most weapons effectiveness analyses - and therefore the most common measure of antipersonnel effect - is the probability of incapacitating an infantry soldier, given a random hit, or P_[I/H]. It has recently been shown that P_[I/H] is closely correlated to the expected kinetic energy deposit (EKE) in the "average" soldier struck at random by a particular projectile.''

The ΔE₁₅/EKE parameter has no relationship to psychological effects; it is a physical measure of projectile kinetic energy expenditure.

And while most that old thinking under appreciating the most important metrics of Pen/Exp/Wound Volume perhaps E15 is that extra thing not being considered?

Or has that been totally disregarded now and if so why?

Certainly .357mag/Sig seemed to have had quicker changing of behavior in bad guys than similar 9mm close equivalent JHPs/bullet weights and yet they shouldn't on paper when ignoring velocity/ME/E15.
Bigger bullet more wound volume is every time but is e15 the other metric being ignored?

While I have included ΔE₁₅/EKE calculations in past contributions, I have not done so for quite some time. The controversial nature of the methodology led to complaints, so I don't offer them here anymore; I still do so on other forums. If you need a ΔE₁₅/EKE for a particular case, I can provide it to you via PM.

Is there a simple way to plug and play figure out the E15 for each load tested or if you have Organic Gel Data? Please explain how to do that I find you including that metric interesting and wonder what readings would discuss this?

Unfortunately, there is no 'easy button'.

In order to determine the ΔE₁₅/EKE of a test projectile, you would need high frame rate videography of the test in 10% ordnance gelatin from which the test projectile's instantaneous velocity can be determined at both depths. Using that data, the test projectile's ΔE₁₅/EKE could be computed.

The mathematical basis for this process is addressed in the technical paper referenced earlier in this post:

''The EKE from random hits on actual enemy soldiers cannot be measured: but EKE may be approximated by:

EKE = ∫_o^xmax F(x)P(x)dx

where F(x) is the retarding force on the projectile as a function of depth of penetration, x, into a 20% gelatin block, P(x) is the probability that the projectile would still be within the "average" soldier at depth x, given a random hit, and x_max is the maximum gelatin penetration depth of the projectile. F(x) is usually calculated from time-penetration data derived from high-speed movies of gelatin impacts. However, if the gelatin retardation could be predicted from a mathematical model, then the predicted F(x) could be used to calculate EKE. Since P(x) is already known, EKEs derived in this manner would require no firing. In fact, EKEs could be predicted for purely hypothetical projectiles.''

Any of the five existing mathematical bullet penetration models—the mTHOR algorithm (Schwartz, 2014), Q-model (Schwartz, 2012), WTI (MacPherson, 1995), UTSI (Peters, 1990), and US Army BRL (Sturdivan, 1973)—can be rearranged algebraically to perform the ΔE₁₅/EKE calculation for both hypothetical and actual tests.

[Ghost Dog]

I'll do the best that I can.



Predicted cavity volume is computed by multiplying the square of the expanded bullet's cross-sectional radius, r², times π (�3.1415927), times the length, L, of the permanent cavity, times a projectile-specific configuration factor, Φ, or V = π·r²·L·Φ



ΔE₁₅ is the amount of kinetic energy that a given projectile expends as it traverses a penetration depth of 1 centimeter to 15 centimeters through soft tissue or 10% ordnance gelatin test medium. The ΔE₁₅ parameter (in later research referred to as EKE or expected kinetic energy) is still in use by the US military today in the ballistic insult subroutine contained within the ORCA/MUVES-S2 SLV software that has been used successfully to match the capability of our small arms munitions to those of our adversaries' munitions over the last 50+ years. The ΔE₁₅ parameter is still relevant and not being ignored.

Due to technical misunderstanding and confusion, some researchers have chosen to ignore or discount the use of the ΔE₁₅ (or EKE) parameter mistaking it as a direct causal mechanism of tissue damage and incapacitation rather than as a correlative factor. If you wish to read the technical paper in which the ΔE₁₅/EKE parameter is correctly discussed, I would refer you to, A Mathematical Model for Assessing Weapons Effects From Gelatin Penetration by Spheres (AD-770352); Sturdivan, LM; Edgewood Arsenal, SAREA-BL-BS, Aberdeen Proving Ground, MD, 21010, September, 1973.

Here is a very brief excerpt from that source explaining the concept in simple terms:


The ΔE₁₅/EKE parameter has no relationship to psychological effects; it is a physical measure of projectile kinetic energy expenditure.



While I have included ΔE₁₅/EKE calculations in past contributions, I have not done so for quite some time. The controversial nature of the methodology led to complaints, so I don't offer them here anymore; I still do so on other forums. If you need a ΔE₁₅/EKE for a particular case, I can provide it to you via PM.



Unfortunately, there is no 'easy button'.

In order to determine the ΔE₁₅/EKE of a test projectile, you would need high frame rate videography of the test in 10% ordnance gelatin from which the test projectile's instantaneous velocity can be determined at both depths. Using that data, the test projectile's ΔE₁₅/EKE could be computed.

Barring that, any of the five existing mathematical bullet penetration models—mTHOR algorithm (Schwartz, 2014), Q-model (Schwartz, 2012), WTI (MacPherson, 1995), UTSI (Peters, 1990), and US Army BRL (Sturdivan, 1973)—can be rearranged algebraically to perform the ΔE₁₅/EKE calculation for both hypothetical and actual tests.

The mathematical basis for this process is addressed in the technical paper referenced earlier in this post:


The five existing mathematical bullet penetration models can be used to perform these kinds of calculations.

First off, thank you for the response, though a lot here is difficult.

Delving into E15/EKE territory acknowledging that 1st and foremost PROPER PENETRATION must be present, then Expansion, and therefore Wound Volume causing blood loss.....

But wondering what part E15 MAY PERHAPS play (in combination with often being a louder cartridge, sometimes more flash, as well as a higher physical pressure wave blast of expanding gases at closer ranges hitting the subject) in someone realizing they have been shot, which many, but not all (such as dedicated attackers/Platt etc.) will than have psychological reaction causing behavioral changes (running away, keeling over, dropping to the ground as if hit by lightning, FIBS) ie .357 Sig/Mag vs 9mm often or common reactions and to some extent +p+ vs standard pressure reactions (let's say outside of CNS or Heart shots-obviously anything reaching cns or heart will be somewhere between somewhat to totally effective). Ie while a good hunter can certainly kill deer with a well placed 9mm, it's easier and considered more ethical, and illegal vs legal in many states to do so with similar diameter but faster velocity .357 magnum...the shot can be a little less well placed and still be ethically effective.

For my purposes all are pistol JHP's, so what does this mean "times a projectile-specific configuration factor", and would it change for each round or handgun caliber? Or can I plug and play expanded r2, Penetration in inches, times 3.1415927? What is this specific configuration factor or how to calculate that? Is a 9mm JHP starting diameter different than a .45 JHP for plugging into this equation to figure out wound volume? Or is JHP a constant configuration factor?


I see that in some of the early rounds you gave data for in this thread you gave E15/EKE but stopped because most think it is irrelevant. While the PI may be (for handgun calibers anyways and not rifles), I think E15/EKE may be relevant, at least sometimes. And I believe physiological relates to psychological but would like very much to get some numbers from you.

Do you have any e15 data you would share with me, in PM if desired on any 125 grain .357 Mag/.357 Sig, so I can compare to other calibers or perhaps 158 gr .357 Mag? Similarly, I would love to compare the e15 values for the hotter 155/165 gr .40 loads to 180 gr, and to other caliber grain weights as well. Also, any +p+ 9mm data, to compare to the few you gave e15 to earlier in the thread of standard pressure 9mm like WWB 115 and 147 whose performance is known. Any 124+p Data on a more modern design like Gold Dot or HST? I am curious what a difference in E15 say 9bple +p+ 115 gr was compared to standard pressure 9bp & if there is perhaps correlation there to the difference in real world OIS performance. Plus, wondering if these factors were why Secret Service went with +p+ 115 (Winchester) & then .357 Sig after their Super Secret Study (has anyone ever been granted access to this that is known)?

Your 147 gr WWB/USA water penetration of app 13" being similar to the avg 13" in Organic Gel and the avg 13" in app 41 bodies 27/28 published in study and I believe DrGkr said 14 more with similar results after that in IWBA (not through bone) is interesting.
So water testing expansion for PISTOL bullets or below 1700 fps is 95-99% correlation to Organic Gel though a bit great expansion typically?
Is Water Jug Penetration similarly around 95-99% correlation to Organic Gel Penetration once you divide by X (and this X be that 1.6 or 1.7 is different depending on which method?)
Thank you