Velocity and Muzzle Energy vs Incapacitation

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My sister and brother-in-law are both retired CHP.

My BIL was a CHP firearms instructor. CHP officers absolutely loved .40 S&W 180gr.
Indeed. My buddy became a big believer in the 180gr/.40 load.

That was even though the bulk of their duty loads over the years (beginning with the RA40180HP) were NOT bonded.

I always chuckled how so many folks (and some fed agencies 😉) would get so wrapped up around the axle about the need for 'bonded this brand & bonded that brand', but the largest state patrol agency in the country didn't seem to lose any sleep over it. They were quite satisfied with their 180gr cup & core JHP's (and that was being fired out of 4" 4006 & 4006TSW's, and 3.5" 4013TSW's (for their plainclothes officers).

I did hear how some CHP field offices might sometimes end up acquiring some bonded ammo, like GDHP, when they were faced with being unable to get their regular shipments on the state contract. Like the rest of us, they sometimes had to take what they could scrounge and get when ammunition production was backlogged by several months. Of course, nowadays the CHP has a long list of different ammunition tested which meets the specifications to be on the state contract, and which meets their approval, and which includes more than just .40 S&W. Lots of agencies buy off the contract.

I remember my buddy carried his M60 off-duty, and had to use the W-W 110gr JHP +P+, but that he saw a couple officers on one of the field offices where he worked who carried S&W 10XX guns off-duty, and the carried the W-W 175gr STHP that field office maintained in inventory for quals and off-duty carry.
 
Lucky Gunner gel test data is faulty - because Clear Ballistics Gel.

The 125gr gr Remington .357 Magnum semi-jacketed HP has a scalloped jacket that shears off all the exposed lead at the tip when the bullet impacts, producing several fragments. (Page 15 of Wound Ballistics Review, Vol. 1 No. 4 has a x-ray imagery of this load in both and actual shooting and in properly prepared and calibrated Type 250A ordnance gelatin. (Link)) ( This is the load I carried on patrol when I was armed with a 4" S&W modle 28 Highway Patrolman.)

According to Hornady, its .380 Critical Defense expands to .51" and penetrates 10.25". (Link)

Yeah, the characteristics of the synthetic gel mediums do offer some differences in the way of thinking to determine expansion & penetration measures compared to organic gel (@10%, at the right temperature and checked for 'calibration' with the BB at the right velocity).

Like you, I carried various 125gr Magnum JHP's during the revolver days of my career carrying .357's, but eventually went to carrying 145gr STHP, and wish Remington had continued production of its 140gr SJHP load. I always suspected a lot of the 'velocity is everything' proponents (and non-LE shooting enthusiasts) tended to overlook how the signfificant amounts of exposed lead around the JHP nose cavities could become fragments capable of increasing wounding of tissues along the path of the expanding (fragmenting) JHP bullet. This seemed (to me) to be one of the things the .355 JHP's used in .357SIG couldn't duplicate of the Magnum revolver JHP's. If anything, the bonding methods used in the various loads worked against shedding fragments in different conditions. The Partition Gold load Winchester originally used seemed quite an expander, though.

One from a gel shoot I attended many years ago. The Winchester Partition Gold 165gr JHP (RA401P)
 
In this scenario, bullet size and penetration are virtually identical. The only difference is the speed at which the handgun bullet leaves the barrel and hits the target.
perhaps it has to do with the energy the bullet is carrying at earlier penetration distances. Imo, final expansion is only part of it, as the widest expansion occurs earlier before the pedals/mushroom fold back. Bodies have wide variety of densities in them, including bone. Again imo, companies are specifically designing bullets to meet specific criteria, as in final dia and penetration depth.
 
Another comparison using the 357 Mag from above.
https://www.luckygunner.com/labs/self-defense-ammo-ballistic-tests/
357 Mag 4'' Remington 125 SJHP - 13.6'' / .54 - 1,473 fps - 602# KE
380 Hornady 90 gr. FTX Critical Defense - 13.2'' / .52 - 910 fps - 166# KE
Very similar penetration and expansion in gel.
If one thinks KE doesn't matter then they should think those two bullets have about the same ASAP incapacitation potential.

My opinion is that it's not that KE doesn't matter, it's that it's simply one part of a larger picture.

Yes, KE DOES matter. It's just not the be-all of terminal ballistics, by a long shot.

To that end, yes, velocity is important, but not just for KE. Momentum is fantastically important as well (which is also directly proportional to velocity). And a significant number of other factors are required to fully evaluate terminal ballistics.

Also, I dislike comparing different calibers because too many other important variables are affected. For example, if you change calibers, but retain mass and velocity, then you will RADICALLY affect penetration characteristics because the cross sectional area of the bullet changed. Cross-caliber comparisons are much more complicated because of this. Better to evaluate within the same caliber, and then minimize the number of characteristics changed within that. E.g., same caliber, same mass, different velocities or same caliber, same velocity, different masses.

Thus my caution to anybody who focuses too much on velocity/KE. It's important...but it's not all that's important in terminal ballistics.
 
I'll say it again and I don't think it can be overstated, energy is a meaningless number. That is not to say it doesn't exist or that it isn't in play but that the use of 'that' number in 'this' context is meaningless for two reasons.

1) If two cartridges with completely dissimilar energy levels can create the same result on the same critter; if two cartridges with identical energy levels can have entirely different results on the same critter, then why are we even talking about it?

2) Unless we are able to determine how much of that energy is used to damage tissue, versus how much is wasted on friction, how much is absorbed by the soft tissues and how much is carried out of the target after it exits, what does it really tell us?

The "potential" to do work is irrelevant. I had the potential to be a brain surgeon. So what?
 
1) If two cartridges with completely dissimilar energy levels can create the same result on the same critter; if two cartridges with identical energy levels can have entirely different results on the same critter, then why are we even talking about it?
We talk about bullet diameter and bullet mass even though two bullets with different diameter or different mass can create the same result and two bullets of the same diameter or the same mass can have entirely different results on the same critter. Does that mean mass and bullet diameter are absolutely meaningless? Or do they provide some valuable insight while not giving us the entire answer?
The "potential" to do work is irrelevant. I had the potential to be a brain surgeon.
Potential is pretty important.

You had the potential to be a brain surgeon, but not everyone does. If you want someone to be a brain surgeon, it's important to have an idea of their potential before you expend a lot of time and effort and money trying to prepare them for a job they will never be able to do. Does everyone with the potential to be a brain surgeon become one? Would everyone who has the potential to be a brain surgeon actually be a good one?

The answer is no, and all the same questions and observations apply to the question at hand. Potential does tell you something, but it's only a small part of the puzzle. It is important to understand because you don't want to try to get blood from a turnip, so to speak. If a particular caliber doesn't have the potential (energy) to do what you want it to do, say expand and still penetrate 12-18" reliably, then maybe you want to look at a cartridge with more potential rather than expending time, effort and energy trying to make the cartridge do something it really can't do. Now, just because you pick a caliber with the potential to do the job, does that guarantee success? No, it doesn't. It just gives you a chance at it.
That "energy dump" accomplishes two things: the poking of holes, and the conversion of kinetic energy to heat energy--simple physics. The heat is not a player in this.
I don't like the term "energy dump" because it oversimplifies things. Kinetic energy is what is expended when a bullet makes noise when it hits the target, when it makes holes by damaging/displacing tissue, when it generates temporary cavity, when it breaks bones and when it deforms itself.

It's not like there's a load of energy, it all gets dumped into the target and the energy itself all goes to doing one thing. For example, the energy used up expanding the bullet doesn't really get dumped into the target at all, it "goes into" the bullet resulting in deformation of the metal and ultimately in heat generation. Once the bullet is expanded, it is considered more effective, so we see the loss of energy required to expand it as beneficial, but all the same, that's energy that won't be available to damage the target. An expanding bullet won't penetrate as deeply as a non-expanding bullet with the same mass and impact velocity, even after one takes into account that it has a larger frontal area. That's because some of the bullet's kinetic energy was used up deforming (expanding) itself and that's energy that is no longer available to generate penetration.

The best way to think of a bullet wound is as a combination of a penetrating wound (like you would get from stabbing someone with a sharpened rod) and a blunt trauma. The blunt trauma effect is from the temporary cavity.

The lower the energy, the less blunt trauma effect you get and at the very low end of the scale, it can act almost like a pure penetration wound. The blunt trauma effect in handguns is not enough to tear elastic tissues, but it is something that will likely get noticed while a pure penetrating wound can escape a person's attention in the middle of a fracas. More than once I've heard a stabbing victim say they thought they were being punched and only later realized that they were being stabbed. I've also seen a few instances where people were shot by lower powered cartridges and didn't notice until later. We can see then, that pure penetration can go unnoticed. A decent sized temporary cavity will feel something like being struck, and will cause bruising type injuries by the same mechanism that a striking object would. It stretches/deforms tissue and small blood vessels rupture when they reach their elastic limit. Nerves in the tissue are traumatized by the same mechanism, causing pain. Temporary cavity, in some circumstances can cause tissues that are not elastic to rupture but that's not something you can count on since that type of tissue is not uniformly distributed around the body.

What you can count on is that if the temporary cavity is sufficient, the attacker will almost certainly know they've been shot unless they are not in their right mind (crazy, drugged up, etc.). That doesn't do anything in terms of physical incapacitation, but the dirty little secret of handgun self-defense is that physical incapacitation is often not what ends up stopping attacks. In many cases, what stops attacks is the attacker's realization they've been shot motivating them to give up. One study suggested that over 80% of successful defensive gun uses did not involve the attacker being physically incapacitated. Which means that it's very important for the attacker to get a "notification" that they have been shot and that's part of what temporary cavity does for the defender.

The penetration aspect of the bullet wound is what actually does the physical incapacitation, but the temporary cavity messes with the attacker's mind and helps with psychological stops.

This is why attackers who are crazy or heavy into substance abuse at the time of an attack can be ridiculously difficult to stop. It's not that the bullets somehow are less effective on them--that obviously makes no sense. It's that their brain doesn't get the "notification" that they have been shot and therefore they keep going until something they need to keep attacking actually quits working. They run out of blood, a big bone gets broken, the heart stops pumping, the brain gets scrambled, and they can no longer go on. We've all heard about the horror stories. But EVERY shooting can be like that if attackers don't realize when they have been shot. That is one reason why the "notification effect" is valuable even when there's no significant wounding generated by it.

Another reason temporary cavity can help out is sort of similar. Because it does get noticed, it is a distraction. I know I don't shoot as well (or think as well) when I'm being distracted, and I believe that's a pretty common failing amongst humans. Once a defender starts getting hits on an attacker, even if they aren't physically incapacitating hits, if the attacker is feeling those hits, it's safe to say that the distraction is going to impact their performance and give the defender an extra edge. Part of "winning" is not just getting the bad guy stopped, it's also not getting killed in the process, so anything that disrupts the attacker's ability to make good shots is a very good thing.

This is part of why focusing exclusively on wounding hasn't provided a good answer for the caliber question. When it comes to shooting human attackers, there's much more to whether the attacker stops and the defender survives than the pure "wounding" effect of the bullet.
 
We talk about bullet diameter and bullet mass even though two bullets with different diameter or different mass can create the same result and two bullets of the same diameter or the same mass can have entirely different results on the same critter. Does that mean mass and bullet diameter are absolutely meaningless? Or do they provide some valuable insight while not giving us the entire answer? Potential is pretty important.

You had the potential to be a brain surgeon, but not everyone does. If you want someone to be a brain surgeon, it's important to have an idea of their potential before you expend a lot of time and effort and money trying to prepare them for a job they will never be able to do. Does everyone with the potential to be a brain surgeon become one? Would everyone who has the potential to be a brain surgeon actually be a good one?

The answer is no, and all the same questions and observations apply to the question at hand. Potential does tell you something, but it's only a small part of the puzzle. It is important to understand because you don't want to try to get blood from a turnip, so to speak. If a particular caliber doesn't have the potential (energy) to do what you want it to do, say expand and still penetrate 12-18" reliably, then maybe you want to look at a cartridge with more potential rather than expending time, effort and energy trying to make the cartridge do something it really can't do. Now, just because you pick a caliber with the potential to do the job, does that guarantee success? No, it doesn't. It just gives you a chance at it.
I don't like the term "energy dump" because it oversimplifies things. Kinetic energy is what is expended when a bullet makes noise when it hits the target, when it makes holes by damaging/displacing tissue, when it generates temporary cavity, when it breaks bones and when it deforms itself.

It's not like there's a load of energy, it all gets dumped into the target and the energy itself all goes to doing one thing. For example, the energy used up expanding the bullet doesn't really get dumped into the target at all, it "goes into" the bullet resulting in deformation of the metal and ultimately in heat generation. Once the bullet is expanded, it is considered more effective, so we see the loss of energy required to expand it as beneficial, but all the same, that's energy that won't be available to damage the target. An expanding bullet won't penetrate as deeply as a non-expanding bullet with the same mass and impact velocity, even after one takes into account that it has a larger frontal area. That's because some of the bullet's kinetic energy was used up deforming (expanding) itself and that's energy that is no longer available to generate penetration.

The best way to think of a bullet wound is as a combination of a penetrating wound (like you would get from stabbing someone with a sharpened rod) and a blunt trauma. The blunt trauma effect is from the temporary cavity.

The lower the energy, the less blunt trauma effect you get and at the very low end of the scale, it can act almost like a pure penetration wound. The blunt trauma effect in handguns is not enough to tear elastic tissues, but it is something that will likely get noticed while a pure penetrating wound can escape a person's attention in the middle of a fracas. More than once I've heard a stabbing victim say they thought they were being punched and only later realized that they were being stabbed. I've also seen a few instances where people were shot by lower powered cartridges and didn't notice until later. We can see then, that pure penetration can go unnoticed. A decent sized temporary cavity will feel something like being struck, and will cause bruising type injuries by the same mechanism that a striking object would. It stretches/deforms tissue and small blood vessels rupture when they reach their elastic limit. Nerves in the tissue are traumatized by the same mechanism, causing pain. Temporary cavity, in some circumstances can cause tissues that are not elastic to rupture but that's not something you can count on since that type of tissue is not uniformly distributed around the body.

What you can count on is that if the temporary cavity is sufficient, the attacker will almost certainly know they've been shot unless they are not in their right mind (crazy, drugged up, etc.). That doesn't do anything in terms of physical incapacitation, but the dirty little secret of handgun self-defense is that physical incapacitation is often not what ends up stopping attacks. In many cases, what stops attacks is the attacker's realization they've been shot motivating them to give up. One study suggested that over 80% of successful defensive gun uses did not involve the attacker being physically incapacitated. Which means that it's very important for the attacker to get a "notification" that they have been shot and that's part of what temporary cavity does for the defender.

The penetration aspect of the bullet wound is what actually does the physical incapacitation, but the temporary cavity messes with the attacker's mind and helps with psychological stops.

This is why attackers who are crazy or heavy into substance abuse at the time of an attack can be ridiculously difficult to stop. It's not that the bullets somehow are less effective on them--that obviously makes no sense. It's that their brain doesn't get the "notification" that they have been shot and therefore they keep going until something they need to keep attacking actually quits working. They run out of blood, a big bone gets broken, the heart stops pumping, the brain gets scrambled, and they can no longer go on. We've all heard about the horror stories. But EVERY shooting can be like that if attackers don't realize when they have been shot. That is one reason why the "notification effect" is valuable even when there's no significant wounding generated by it.

Another reason temporary cavity can help out is sort of similar. Because it does get noticed, it is a distraction. I know I don't shoot as well (or think as well) when I'm being distracted, and I believe that's a pretty common failing amongst humans. Once a defender starts getting hits on an attacker, even if they aren't physically incapacitating hits, if the attacker is feeling those hits, it's safe to say that the distraction is going to impact their performance and give the defender an extra edge. Part of "winning" is not just getting the bad guy stopped, it's also not getting killed in the process, so anything that disrupts the attacker's ability to make good shots is a very good thing.

This is part of why focusing exclusively on wounding hasn't provided a good answer for the caliber question. When it comes to shooting human attackers, there's much more to whether the attacker stops and the defender survives than the pure "wounding" effect of the bullet.

Lotsa really good stuff here.

Looking back over this entire thread, it seems to me that people in general tend to conflate "physics" with "terminal ballistics".

While physics IS in play, that's not what terminal ballistics is all about. Terminal ballistics is ultimately all about the physical effects on a biological organism, whether that be human or animal under whatever circumstances (such as self-defense or hunting).

Physics is about energy conversion, conservation of momentum, impulse, Newtons' Law, blah, blah, blah. A bullet fired into a target in which it remains within the target has all of its energy converted into heat energy (the majority) and sound energy (a small fraction of the total). That's physics.

Terminal ballistics is all about penetration and damage to the organism, which ultimately leads to the desired goal of stopping the organism (from attacking in the case of self-defense or from running away in the case of hunting, for example). A bullet fired into a target in which it remains within the target pokes holes in organs, causes blood loss, damages nerves, shreds tissues, destroys organs, breaks bones, ricochets somewhere, causes shock, induces some psychological impact, etc. That's terminal ballistics.

OBVIOUSLY you need velocity. A bullet that doesn't move has no terminal ballistics, right? And OBVIOUSLY you need a significant amount of velocity, because a bullet traveling too slow to penetrate doesn't do much either. But it isn't just the KE any given bullet has which causes the various terminal ballistics results. Other factors contribute significantly to terminal ballistics.

As an extreme example let's use the instance of a 5 1/4 ounce baseball thrown at 100 mph by Ryan Nolan and a 40 grain .22 LR at 1,100 fps.

The baseball (2,297 grains at 147 fps) has a KE of 110 ft-lbs.

The .22 LR (40 grains, 1,100 fps) has a KE of 107 ft-lbs.

Virtually identical KE, and I dare say they will produce radically different terminal ballistics.


Using these same extreme example for the baseball and bullet, let's use an extreme example for the biological targets:

A 20 ounce squirrel rooting around in the snow for a walnut and a 180 pound man wearing a winter jacket watching the squirrel from his porch.

Virtually identical KE again, but the terminal ballistics on these two radically different biological targes will be even MORE different.


There is physics involved, but physics is NOT terminal ballistics.


On a related note, @Frank Ettin has often been quoted on the matter of bullets with respect to the never ending debate over what's "best". What he's noted very much relates to terminal ballistics. I suppose we COULD make one revolving around physics, but those will be very much conditional. For example, "faster bullets are better than slower bullets"...but this doesn't work under all circumstances because bullet design comes into play (like hollowpoints are designed for optimal expansion in a given velocity range).

Frank's rules of thumb:

So as a rule of thumb --
  • More holes are better than fewer holes.
  • Larger holes are better than smaller holes.
  • Holes in the right places are better than holes in the wrong places.
  • Holes that are deep enough are better than holes that aren't.
  • There are no magic bullets.
 
We talk about bullet diameter and bullet mass even though two bullets with different diameter or different mass can create the same result and two bullets of the same diameter or the same mass can have entirely different results on the same critter. Does that mean mass and bullet diameter are absolutely meaningless? Or do they provide some valuable insight while not giving us the entire answer? Potential is pretty important.
Diameter and mass are relevant, energy isn't. If you disagree, how is it relevant?

As I said, potential is meaningless. It takes energy to produce the desired result but until we can determine how much is used to destroy tissue and how much is wasted; or how to differentiate a 500ft-lb wound from a 2000ft-lb wound, it tells us nothing. We'd also have to determine how much goes to the width of the wound channel and how much goes to depth. Because a rapidly expanding hollowpoint expending 1000ft-lbs of energy on a target is going to yield a vastly different result from that of a flat-nosed solid that penetrates four feet deep. Even though the energy expended is the same. Let's say they both produce the same volume of wound channel. We'd have to know the depth of that wound channel. In any regard, potential energy tells us nothing.

From shooting large critters, we learn that velocity makes little difference. You can increase the velocity enough to 'look' significant on paper but when the metal meets the meat, it's largely irrelevant. I'm going to use the .44Mag as an example because I have the most data on it.

A 355gr at 1200fps and a 240gr at 1500fps generate the same level of energy of around 1200ft-lbs. Energy worshipers would conclude they would have a similar performance on game. If that game is a 200lb deer, probably true. If that game is Cape buffalo, absolutely not. You can make these comparisons all the way down to 180gr. The 355gr will penetrate nearly DOUBLE that of the lighter bullet. In a critter large enough to catch it, that makes a HUGE difference in terminal effect.

By contrast, throttle the 240gr down to the same 1200fps. The factor that has the greatest effect on energy is velocity, we've made that factor equal. The 240's energy drops to 760ft-lbs. The difference in terminal effect is pretty much the same. Is the drop in energy the reason for the dramatic difference in penetration? Or is it the difference in mass? Which is more meaningful, that it's 440ft-lbs less energy or that we give up 115gr in mass?

It's the difference in mass that makes up the difference. How much energy is produced in the process is irrelevant.

Energy may be a small part of the puzzle, at some point but IMHO, it's best use is as a marketing tool for selling velocity.

EDIT: I'd like to add that I think a lot of the energy generated by high velocity rifle cartridges is simply absorbed by the body. Yes, they do destroy more tissue but I don't think it's directly proportional to energy figures.
 
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Diameter and mass are relevant, energy isn't. If you disagree, how is it relevant?

As I said, potential is meaningless. It takes energy to produce the desired result but until we can determine how much is used to destroy tissue and how much is wasted; or how to differentiate a 500ft-lb wound from a 2000ft-lb wound, it tells us nothing. We'd also have to determine how much goes to the width of the wound channel and how much goes to depth. Because a rapidly expanding hollowpoint expending 1000ft-lbs of energy on a target is going to yield a vastly different result from that of a flat-nosed solid that penetrates four feet deep. Even though the energy expended is the same. Let's say they both produce the same volume of wound channel. We'd have to know the depth of that wound channel. In any regard, potential energy tells us nothing.

From shooting large critters, we learn that velocity makes little difference. You can increase the velocity enough to 'look' significant on paper but when the metal meets the meat, it's largely irrelevant. I'm going to use the .44Mag as an example because I have the most data on it.

A 355gr at 1200fps and a 240gr at 1500fps generate the same level of energy of around 1200ft-lbs. Energy worshipers would conclude they would have a similar performance on game. If that game is a 200lb deer, probably true. If that game is Cape buffalo, absolutely not. You can make these comparisons all the way down to 180gr. The 355gr will penetrate nearly DOUBLE that of the lighter bullet. In a critter large enough to catch it, that makes a HUGE difference in terminal effect.

By contrast, throttle the 240gr down to the same 1200fps. The factor that has the greatest effect on energy is velocity, we've made that factor equal. The 240's energy drops to 760ft-lbs. The difference in terminal effect is pretty much the same. Is the drop in energy the reason for the dramatic difference in penetration? Or is it the difference in mass? Which is more meaningful, that it's 440ft-lbs less energy or that we give up 115gr in mass?

It's the difference in mass that makes up the difference. How much energy is produced in the process is irrelevant.

Energy may be a small part of the puzzle, at some point but IMHO, it's best use is as a marketing tool for selling velocity.

EDIT: I'd like to add that I think a lot of the energy generated by high velocity rifle cartridges is simply absorbed by the body. Yes, they do destroy more tissue but I don't think it's directly proportional to energy figures.

Well put.
 
...To that end, yes, velocity is important, but not just for KE. Momentum is fantastically important as well (which is also directly proportional to velocity). And a significant number of other factors are required to fully evaluate terminal ballistics.
...

Thus my caution to anybody who focuses too much on velocity/KE. It's important...but it's not all that's important in terminal ballistics.
This is a prudent observation.

Mass and momentum do seem to play significant roles. The speed of the impacting bullet can play into things, but it's contribution seems to be both variable and unpredictable ... and then there's the critical importance of the anatomical area(s) affected by the GSW.

Since another description of KE is the ability to do work, we can't just rely upon the simple speed part of the equation, but must also consider how the design and construction of the bullet involved may be able to translate that speed into the sort of work we hope to have done.

I remember hearing and learning of a lot of cops who were Magnum service revolver users who were quite satisfied with the 158gr loads, and by that I mean JHP, JSP and even LSWC style bullets. (Consider how the .38SPL 158gr LSWCHP +P load had quite a following of satisfied users, among those who weren't allowed to carry ammunition with the PR black eye of "MAGNUM". ;) )

The middleweight (125gr-145gr) loads seem to generate their fair share of satisfied users, too. The .38SPL versions of middleweight loads seemed to be a little more unpredictable. Reports of a lack of expansion at lower speeds. The speed of the old style .38SPL & +P loads seemed to show that more speed meant a better chance of achieving expansion. And the beat went on ...

The 110gr users? That's where the 'street' results started to include some reports of insufficient penetration to reach critical anatomical tissues, structures and organs. Of course, this overlapped the reports of the .38SPL 110gr +P+ load, which saw a lot of use (becoming the issued load of the CHP in the waning days of service revolvers).

Bullet weight (mass), design, diameter (caliber), speed and momentum all came together, in just the right combinations at times to make the right Goldilocks porridge.

Of course, there was always (and remains) the way some folks seem to mistakenly conflate muzzle blast and felt recoil with potential 'stopping power effectiveness'. Doesn't exactly help clear up the picture. ;)

You know the primary factor that sometimes makes me put a LCP back into the safe and grab a .38SPL snub? When I consider the lighter bullet weight of the .380 loads versus the .38 loads. Of course, then there's the gray area of when I have one of my LCP's loaded with Rem 102gr BJHP/HPJ loads, and an older J-frame loaded with standard pressure 110gr JHP or FTX loads. How similar are those, in the real world, at least when it comes to bullet weight and speed? Dunno. However, the modern 125gr, 130gr & 135gr .38SPL loads do seem to generate reports of effectiveness. Even the old-style 158gr LSWCHP/LHP +P, although not as much 'in favor' as in previous years, somehow still seem able to continue to 'work' when fired from shorter barreled guns. And the beat goes on ...

How about the venerable 148gr all-lead TWC? Still some proponents of that low-recoiling load, and it's less punishing on shooters than many of the +P, and even standard pressure, .38SPL loads, especially when fired from smaller and lighter guns.

Where's the magic line just denoted by speed, again?
 
Of course, there was always (and remains) the way some folks seem to mistakenly conflate muzzle blast and felt recoil with potential 'stopping power effectiveness'. Doesn't exactly help clear up the picture. ;)

Yep.

And as for "stopping power"...

"Stopping power" is one of those nebulous (read: BS) terms that I refer to as a sales gimmick. It has no measurably definable characteristics and people will use it as another vague, fancy-sounding descriptive to attribute to any particular aspect of a firearm's capabilities. And this is in spite of the equation(s) some people have made up for it.

All it really means is "the ability of a given bullet to incapacitate its target". And we've already got several posts in this thread which bring out the fact that terminal ballistics is a complex subject with many variables and many uncertainties.
 
I'll say it again and I don't think it can be overstated, energy is a meaningless number. That is not to say it doesn't exist or that it isn't in play but that the use of 'that' number in 'this' context is meaningless for two reasons.
It's no more meaningless than any other single factor, without context.
Mass and velocity are meaningless without the other one.
 
There is physics involved, but physics is NOT terminal ballistics.
Well, terminal ballistics is physics. The problem is that there’s a lot more to what happens when you shoot a living creature than just the simple math that gets knocked about in typical discussions like this one.
Diameter and mass are relevant, energy isn't. If you disagree, how is it relevant?
Kinetic energy was shown, several centuries ago, to be the scientific quantity that relates to the ability of a projectile to do work. If that isn’t relevant to the ability of a projectile to do work, I don’t know what is. 😁 The problem is that when the target medium is a combination of elastic and inelastic material, some of which is critical to short term survival, some of which is nearly totally superfluous, and the projectile itself can deform, things get very, very complex.

If you carefully constrain all those variables, eliminate elasticity and go to a carefully calibrated homogeneous target medium, then energy will tell you the whole story. In the world of shooting living things with all the real-world variables involved, the insight it provides is tremendously reduced--or rather it becomes very, very complicated to try to relate kinetic energy to specific shooting outcomes. That doesn’t make it irrelevant, but it does mean that what you can predict based purely on energy is very, very limited. Just as what you can predict based purely on projectile mass is very, very limited, or what you can predict based purely on projectile velocity is very, very limited.
Because a rapidly expanding hollowpoint expending 1000ft-lbs of energy on a target is going to yield a vastly different result from that of a flat-nosed solid that penetrates four feet deep. Even though the energy expended is the same.
Right. Just as you could have two bullets with identical mass and diameter and still have them cause vastly different wounds and have vastly different results on target even though mass and diameter are both relevant. In fact, in the example you give, the mass and diameter of the two bullets could be the same and your statement would still be true. Because mass, velocity, energy, diameter, expansion, etc. are all only parts of the puzzle. Trying to take any one of them and pretend it’s the whole answer results in nonsense. Trying to dismiss any of them results in obvious contradictions. Taking any of them to extremes (making mass or diameter or velocity extremely high or extremely low) results in silliness.
Energy worshipers would conclude they would have a similar performance on game.
I suppose that’s exactly what one would expect from anyone who could reasonably be called an “energy worshiper”. Anyone who “worships” any single parameter relating to terminal ballistics is going to be easily tripped up by real-world counter-examples. Trying to assess the performance on game with just energy, or just bullet mass, or just bullet diameter, or just bullet momentum, or just using made up ratings like TKO, or any other single number is not going to provide an accurate picture of what’s going on. It’s like saying that since two people hunt with the same caliber, they will be equally good hunters. There’s just so much more to it than that.
We can have a more productive discussion about terminal ballistics without ever mentioning energy.
Well, in reality, it is quite difficult to have a meaningful discussion about terminal ballistics without mentioning energy since it is an integral part of the topic. I'm not talking about opinions, I'm talking about reality. Like it or not, kinetic energy is as much a part of terminal ballistics as mass, velocity, expansion, etc. Again, it's not going to tell you the whole story, any more than someone could predict the outcome of a shooting with nothing more than the mass of the bullet involved to work with. But trying to leave it out entirely will handicap a person's understanding of the topic, regardless of whether they believe it or not.

There are a lot of resources on Terminal Ballistics out there that are available for perusal. Start looking at them and see how far you get before energy is mentioned. There's a reason it comes up in any scientific treatment of the topic.
 
Trying to take any one of them and pretend it’s the whole answer results in nonsense.
I know, that's the point. For decades kinetic energy has been used as a single factor answer. When really it's no answer at all. TKO is actually a useful number but only when used as intended, comparing large diameter solids to each other. Which is actually the context in which energy is the most useless.


I suppose that’s exactly what one would expect from anyone who could reasonably be called an “energy worshiper”. Anyone who “worships” any single parameter relating to terminal ballistics is going to be easily tripped up by real-world counter-examples.
Again, people have been doing this for decades, if not a century.


Well, in reality, it is quite difficult to have a meaningful discussion about terminal ballistics without mentioning energy since it is an integral part of the topic.
No it isn't. In "reality", no one can aptly describe the role it plays because as I've said multiple times, there is no way to determine how much of that energy is being used in a productive manner and how much is lost in other ways. All one can do is calculate how much is being generated at a given velocity. In reality, it serves no purpose and is easily rendered useless with just a handful of examples as those I've given.


There are a lot of resources on Terminal Ballistics out there that are available for perusal. Start looking at them and see how far you get before energy is mentioned. There's a reason it comes up in any scientific treatment of the topic.
Energy may be mentioned in the abstract. No one said it didn't exist. As a lifelong handgun hunter among a group of lifelong handgun hunters, we've fought this battle for decades. IMHO, only when you achieve a greater understanding of the topic, when you see 500ft-lbs do the same job as 2000ft-lbs on a first hand and repeatable basis, do you realize that energy is an absolutely useless number. The folks who cling to energy as a measure of lethality are like those who cling to the outhouse after the invention of outdoor plumbing.
 
Placement + adequate penetration.

In the context of a torso hit:
  • If a handgun bullet isn't placed where it will damage vitals (heart, major vessels, or upper spinal cord) then it won't compel a determined aggressor to quickly stop.
  • Likewise, if a handgun bullet doesn't penetrate deeply enough to reach and pass through the heart or major vessels, or disrupt the spinal cord, then it won't compel a determined aggressor to quickly stop.
Poor placement = miss.

Poor penetration = miss.

Everything else doesn't matter.
 
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People and animals can react very differently to identical shots. My roommate had half his leg blown off in combat and didn't know it until he tried to stand up. I am a big believer in heart shots. Either DRT or very shortly and always certainly. People and animals can survive head shots. Of course, people are not going to agree on that either. My point is that it is much more important that you make good shots than what you shoot with. There are times when the weapon or caliber is important as well but so is rate of fire and having a weapon when you need it. A .44 Mag in the safe isn't as useful as a .380 in the pocket if something happens. I don't know if this helps anymore than pushing pet ideas. Interesting topic and comments.
 
Placement + adequate penetration.

In the context of a torso hit:
  • If a handgun bullet isn't placed where it will damage vitals (heart, major vessels, or upper spinal cord) then it won't compel a determined aggressor to quickly stop.
  • Likewise, if a handgun bullet doesn't penetrate deeply enough to reach and pass through the heart or major vessels, or disrupt the spinal cord, then it won't compel a determined aggressor to quickly stop.
Poor placement = miss.

Poor penetration = miss.

Everything else doesn't matter.

True.

And is why I included this in my first comment back in post #71:

Kinetic energy, velocity, mass, momentum, bullet design, and even the target itself all figure into terminal ballistics. And several other aspects in addition, including real world factors such as recoil control and even concealability.


For pistol (and rifle) rounds, if you don't hit the target, then all the fancy numbers you can calculate given velocity, mass, diameter, etc. mean essentially nothing with respect to terminal ballistics.

HOWEVER...the basic assumption here is that the issue of hitting the target is not in question. It's what the bullet can do at that point, and how you can determine whether or not any given round will be effective, which is being discussed.

To that end, what several of us are pointing out is that velocity/kinetic energy is only a part of a very big whole and, by itself, is effectively meaningless without considering it within the scope of the whole.

You can make generalities, of course...but even then there will be holes in those generalities which show up in the terminal ballistics themselves.
 
A car at 2 mph has more kinetic energy than a 45ACP. And yet I saw a old lady bump into an old man shuffling across the crosswalk in front of the grocery store and penetration was 0".
 
For expanded bullets, rate of spin would matter too.
Aft center of gravity, causing yaw...
The list is endless.
Bottom line is, big deep holes in the right places is what it comes down to...
Also a distinction really has to be made between hydrostatic and sub-hydrostatic velocities, especially when using tools like TKO, which is very useful at slower speeds.
The tendency is usually to overthink the issue...
Gil.
 
For expanded bullets, rate of spin would matter too.
Aft center of gravity, causing yaw...
The list is endless.
Bottom line is, big deep holes in the right places is what it comes down to...
Also a distinction really has to be made between hydrostatic and sub-hydrostatic velocities, especially when using tools like TKO, which is very useful at slower speeds.
The tendency is usually to overthink the issue...
Gil.

Hydrostatic should be completely ignored for anything we could post in this thread.

It's not going to be a consideration for pistols at all.

It's ONLY a consideration for rifles, and then only certain rifles that can achieve high enough velocities with large enough bullets to cause a measurably reproduceable hydrostatic shock wave AND have a measurably reproduceable actual terminal ballistic effect on the target.

It's a neat subject to discuss, in and of itself, but not really when considered within the scope of defensive carry, which is what this thread it about.

I'm pretty sure there is another thread or two which discusses this topic...I seem to recall having run across a few in the past.
 
For decades kinetic energy has been used as a single factor answer.
Right. Which won't work. Just like TKO won't work, just like ANY single factor answer won't work. Not that every factor that can't provide the total answer is wrong--it's just that it takes more than any single factor to get the entire answer.
Again, people have been doing this for decades, if not a century.
And they've been wrong. Just like anyone who's espousing any single factor answer is wrong. But that doesn't mean that all single factors are totally irrelevant. It's just that they can't possibly tell the whole story.
In "reality", no one can aptly describe the role it plays...
Of course they can. Just look at some of the many scientific treatments available to you. Kinetic energy is the what the projectile uses to do its work. Do you believe penetration is important? Kinetic energy is expended to provide penetration. Do you believe expansion affects the outcome of shootings? Kinetic energy is expended to generate expansion. Do you believe velocity is important? Kinetic energy is a function of velocity. Do you believe bullet mass means something? Kinetic energy is a function of mass. That doesn't mean all of the energy gets expended doing useful things, but it's the starting point. As I've said many times now, that's a far cry from being the whole story, but it does provide some very limited insight into the situation.
In reality, it serves no purpose and is easily rendered useless with just a handful of examples as those I've given.
Just as any single factor answer can be shown to be useless if it is considered in isolation as if it provides the entire answer. Mass tells you nothing at all unless you have some idea of velocity--the baseball example that commonly comes up demonstrates this. Diameter is not useful unless you know mass and velocity. And so on. Yet when you take them all together, a picture begins to develop.
...energy is an absolutely useless number...
This is the other end of the pendulum swing and it's just as wrong as claiming that it means everything. It can be useful in context. It can be useless if you try to look at it as if it is an answer in itself. Here's an example.
A car at 2 mph has more kinetic energy than a 45ACP. And yet I saw a old lady bump into an old man shuffling across the crosswalk in front of the grocery store and penetration was 0".
An excellent example of why looking at single factors in isolation can provide no information at all, or even apparently contradictory information, while considering more information starts to provide useful perspective.
 
Right. Which won't work. Just like TKO won't work, just like ANY single factor answer won't work. Not that every factor that can't provide the total answer is wrong--it's just that it takes more than any single factor to get the entire answer.

And they've been wrong. Just like anyone who's espousing any single factor answer is wrong. But that doesn't mean that all single factors are totally irrelevant. It's just that they can't possibly tell the whole story.

Of course they can. Just look at some of the many scientific treatments available to you. Kinetic energy is the what the projectile uses to do its work. That doesn't mean all of the energy gets expended doing useful things, but it's the starting point. As I've said many times now, that's a far cry from being the whole story, but it does provide some very limited insight into the situation.

Just as any single factor answer can be shown to be useless if it is considered in isolation as if it provides the entire answer. Mass tells you nothing at all unless you have some idea of velocity--the baseball example that commonly comes up demonstrates this. Diameter is not useful unless you know mass and velocity. And so on. Yet when you take them all together, a picture begins to develop.

This is the other end of the pendulum swing and it's just as wrong as claiming that it means everything. It can be useful in context. It can be useless if you try to look at it as if it is an answer in itself. Here's an example.

An excellent example of why looking at single factors in isolation can provide no information at all, or even apparently contradictory information, while considering more information starts to provide useful perspective.
I concede, aside from absurd examples and selling velocity. In actual, real world examples, it is a useless number. We're better off looking at the diameter and velocity of baseballs and cars, rather than energy. In all contexts, the components of the energy formula are infinitely more useful than calculated energy. Mass and velocity, we can extrapolate from those but not from meaninglessly multiplying them together. It would mean something if we were trying to knock over steel targets. For flesh, blood and bone, it serves no purpose but to muddy the waters and PREVENT understanding. Because it places WAY too much emphasis on velocity.

TKO actually is useful, in context. Energy is not, in any context. Why? It was derived from real world experience. Not math class.

There is no context in which energy is useful. It is only when we ignore it that we can actually have a meaningful conversation about it.

I have to note, that while there are folks convinced that energy is useful, I have yet to see/hear one explain how. I've given multiple examples of the vast disparity between energy figures and actual terminal effect on live tissue. Some folks seem to have an issue differentiating "energy is a useless number in the context of terminal ballistics" and "energy does not exist".

Also worthy of note, none of this argument has anything to do with terminal ballistics.


This is the other end of the pendulum swing and it's just as wrong as claiming that it means everything.
No it isn't. Maybe you're wrong for clinging to a failed concept.
 
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