Ever since the FBI dropped .40 S&W in favor of 9mm Luger and subsequently stated that according to experiments they had performed, 9mm Luger was equally effective as .40 S&W and .45 ACP, there has been a growing sentiment that Energy Foot-Pounds just don't matter. After all, .40 S&W and .45 ACP deliver anywhere from 150 to 250ft-lbs of energy more than 9mm Luger, so it it's just as effective, then obviously either Energy Foot-Pounds don't matter or otherwise the higher number of ft-lbs generated by larger caliber handgun cartridges isn't enough to make an appreciable difference in ballistics performance.

So that begs the question: Do Energy Foot-Pounds matter? Are they an accurate measure of ballistics performance? And if so, at what point do they begin to matter? How many Energy Foot-Pounds does it take to make a difference in performance?

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Shooting Comfort is bilateral.

Personally, I don't believe the FBI report that the 9mm is just as effective as the 40 and 45's. They will say that modern bullet designs have improved the 9mm's, but that same technology also improved 40 and 45's. I believe the main reason they went back to 9's, was because smaller agents; whether it be a female or small statured males had trouble qualifying with the 40's. So the justification was; well, the 9's are just as good. They also said that 40's were hard on guns and ammo cost is higher than 9's....Okay, that may be somewhat true, but look at the increased performance with the 40's. One caliber that I personally think is an underrated, and often dismissed is the 357 Sig. Lots of energy with superior temporary wound cavity damage and a heck of a wallop. A final note on 40's; you have a wide variety of bullet weights; 180, 165, 155, 135 grains at warp speeds and lots of energy. So, INHO caliber, and energy does matter.

While obviously advances in the design of modern Jacketed Hollowpoint ammunition aren't unilateral and have benefited all cartridges, they have arguably benefited 9mm the most since .40 S&W and .45 ACP was already capable of achieving full expansion and adequate penetration as per FBI/IWBA Testing Protocol, whereas previously 9mm Luger couldn't consistently pass their tests.

In other words, the benefits of modern JHPs are less appreciable in .40 S&W/.45 ACP because they were already capable of meeting the requirements of the FBI, and therefore required no improvement. In fact, making .40 S&W and to a lesser extent .45 ACP penetrate deeper would actually cause them to FAIL the FBI/IWBA tests because if they penetrate deeper than 18" in Ballistics Gel then that would be considered overpenetration and thus become a liability for the FBI due to the inherent risk of collateral damage.

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Shooting Comfort is bilateral.

I think it does matter. It is a given that adequate penetration is needed. It takes energy to drive the bullet to the desired velocity to achieve adequate penetration. If a bullet design does well in law enforcement and ballistic testing, then the muzzle energy is adequate.

However there are manufacturers that push these bullets past their design limits. Too much of a good thing.

I have also found that comparing the same bullet design from one caliber to the other is almost useless. There a very few designs that do well in all self defense calibers.

When I choose self defense ammo, I consider penetration first followed by expansion and then weight retention. Last is muzzle energy.

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Life Is A Gift. Defend it!

I choose a good bonded hollow point bullet making 550 to 600 ft/lbs at the muzzle as a minimum.

The so-called experts and internet gun gurus can say whatever they like- 9mm is a marginal defense caliber- always was and remains so, bullet design notwithstanding.

The old verbiage about females and small males not handling recoil is totally garbage. I've trained thousands of people over the years in LE and the military. The size of the person has no bearing. I've had really big people who were terrible shots and difficult to train. I've trained small females who were able to easily handle any of the large calibers. A person who gets the proper training and learn the basic techniques size does NOT matter.
People who spread that BS makes me wonder if they're trying to compensate for their own shortcomings because the facts sure don't bear out the talk.

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183rd FBINA

Good point. But what does that have to do with muzzle velocity?

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Life Is A Gift. Defend it!

No one ever mentions Elmer Keith wore size 5 1/2 boots and was an extremely small man. Yet he was one of the greatest magnum shooters ever.

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Possum—The other white meat!

Hi Dirty Harry Callahan,

Kinetic energy is a huge concern if you're on the receiving end of it. Hence, survival is the only metric that matters.

Avoid, avoid, avoid, and if that doesn't work, run away. Engage only if no other option is available. If engagement is your only option, don't get shot. A gunfight means a bad guy wants a good guy dead. There is nothing beneficial in that for a good guy.

As a predictive index, I'm more inclined to look at momentum.

I would like to suggest caution when drawing inferences based upon what any law enforcement agency issues. A law enforcement agency might issue a 9MM handgun. However, law enforcement agencies generally have lists of approved handgun and cartridges from which their officers can choose. Hence, an agency might issue a Glock 17 9MM, but its officers might choose to carry a 1911-A1 .45 Auto.

Yeah guys, while I agree with your sentiments about not having to be a big guy to handle recoil and shoot well with more powerful firearms, Kanewpadle is correct that such really isn't the topic of discussion, ergo I'd appreciate it if we could focus on the topic of Energy Foot-Pounds to avoid derailing the thread on a tangent.

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Shooting Comfort is bilateral.

They are explaining a likely reason for the FBI's change
back to 9mm.

Take it as an alternative explanation for that change,
versus your assumption that the change was based on
"foot pounds not mattering."

On this forum, I would wager more than a few will say it does matter. The name S&W and the word "magnum" might as well be partners in a tango.

However science, in particular the field of terminal ballistics, has shown time and time again, that when it comes to pistol caliber wounding factors its the Permanent Crush Cavity; penetration and expansion, that matters second most (proper product placement being most crucial). While it is entirely true that more energy placed into a target is better, common pistol caliber rounds simply don't make enough of it to make for a more serious wound. Human flesh being extremely elastic, can cope with the energy placed into it but pistol caliber rounds. It cannot cope with a bullet expanding and burying itself deeply.

Google a paper titled Handgun Wounding Factors and Effectiveness. Read it in its entirety. Twice. Its only 25 pages (+/-). Note the date it was published. Then note that it continues to be peer reviewed. It still holds up.

No. They do not matter.

.25 ACP is fine for every purpose.

Do Energy Foot-Pounds matter?

Yes and no. Everything else being equal, more KE is better, only it is impossible for KE to change without something else changing, like MV or bullet mass, so everything else is never equal. KE is NOT the single criterion of cartridge effectiveness.

Bullets don't kill or stop people from hurting you by delivering KE, or even by delivering momentum. They do it, when they do it (they often don't), by disrupting the CNS, maybe by structurally damaging a limb, maybe by making the use of a limb painful, maybe by loss of blood, or any of several other processes. Most of these processes involve penetration and cutting or smashing.

Post #12 gives a starting place for learning about this.

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Formerly Model520Fan

Below velocities of 2,200 ft/s, not so much. There isn’t enough KE to permanently damage tissue around the wound track. At pistol velocities momentum is a better indicator of penetration. Bullet design matters too.

Because of all the variables, it’s more accurate to shoot a bullet into ordnance gel (not ballistic gel) to test for penetration and expansion to compare effectiveness than try to calculate it.

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Vegan by proxy.

This is correct.

The priority of using energy measurement as one factor in evaluating bullet terminal performance is helpful. However, because such mathematically calculated influence does not directly relate to terminal performance, it is a less persuasive metric.

Many other variables have as much influence or more. The characteristics of the bullet is first, and that includes weight, shape and design. Then there is velocity and deformation and penetration. When any one of these characteristics do not contribute to the dance adequately, terminal performance is compromised.

The best Bullets/caliber will have consistent terminal performance characteristics that meet set goals. The standard for such testing is the FBI gel tests. While not real world, the conditions are the best we have at the moment to compare disparate ideas on Bullets terminal performance. The FBI test does not claim to be real life—it is only a scientific method for approximating performance.
The matrix is:
1. Penetration between 12-18”, with the lower number considered better. Most non-expanding bullets can meet this standard in bare gel.
2. Expansion of the bullet to 1.5x the beginning diameter of the bullet. Ideally the bullet will continue to hold together to deliver the necessary penetration even after expansion. This is the bigger holes do more damage theory, as long as they are deep enough. Retaining weight after expansion usually results in better expanded penetration.
3. A Bullet that can break through objects on the outside of the body, such as clothing, and/or inside the body, such as bones sinew and muscle. Here is where ME probably comes into play, as obstacles can quickly reduce velocity/design shape and render bullet performance less adequate to continue penetration expanded with retained bullet shape going straight through to the desired depth.
4. The actual path of the bullet through a living target is unpredictable because of barriers and changes in density. It is possible to shoot a target multiple times with effective ammunition and not stop the target. Shot placement is a huge factor for success. The average shooter trained to defensively shoot Center of Mass (CoM) has a poor chance of stopping a fight quickly unless his bullet gets to the spine with sufficient velocity (FPE) to destroy it. Often CoM hits allow an aggressor to continue to fight for 30 seconds to a minute, a time frame within which most gunfights will end.

Because of all these other variables and requirements, FPE is only a factor in choosing a caliber/loading, and it’s a fairly low one. Again, it is a mathematical formula being applied to a real world experience arena that has many (more important) variables.

Prioritizing those variables is penetration, then expansion, then weight retention, then straight tracking to the intended target (spine or head). Velocity is one factor making up FPE, but it does not correlate directly to bullet performance given so many other variables. Mass is another factor, but it too is not an isolated dominant factor in terminal performance effectiveness, especially if it’s velocity is low.

In a mix of variables attempting to predict bullet terminal performance, FPE is there and always will be, but it is one of many somewhat lesser influencers in the caliber, bullet, cartridge load debate. Too many people have lost their lives by bullets that miss many of these parameters.

Priorities in choosing a caliber/load go deeper than just bullet terminal performance. The size, reliability, capacity, shootability, carry convenience, accuracy of the gun all contribute to being able to hit the target in the first place so the bullet can do its work.

The other metric for successful shoots terminating an attack is the number of rounds fired that strike the target effectively. The one shot stop with a defensive handgun is a rarity. Multiple shots hitting, 3-5, especially aimed toward spine or head, will do the job quickly, and may even do it with two substandard hits then one coup d’ grace.

FPE is not irrelevant, it is just not very determinative in selecting caliber/cartridge combos for killing felons because of so many other more important factors.

Does energy matter? Let's use some exceedingly applicable analogies for fun.

-Does energy matter to Lebron James when he vaults himself through the air to stuff somebody off the backboard?
-Does energy matter when a batter hits the ball right back into the pitcher's nose at 120 miles per hour?
-Does energy matter when JJ Watt crushes a hapless quarterback?
-Does energy matter when you are shooting at bowling pins in competition?
-Does energy matter when you are hunting grizzly bears?

If you answered yes to one or more of these questions you now have your answer. Call it foot-pounds, call it Kinetic energy, call it joules, call it whatever you want, but energy absolutely matters.

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Ban this man,
'89

Because someone says the reason for going to 9mm is because females and small males can't handle the recoil of higher energy rds. Totally bogus assertion.
And the thread is about muzzle foot-lbs, not muzzle velocity.

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183rd FBINA

I believe this is consistent with responses to contributions posts that refutes cherished beliefs.

Normal conversations do not follow ordained rules. They pursue knowledge. Knowledge is often found resting upon tangents not considered by initial questions/theses.

However, in order to placate, the answer is a qualified no.

BTW, if you have knowledge of your objective, it becomes much easier to find correct answers. Therefore, tell us your objective.

There are a few who are blinded by love of their favorite cartridge that they'll pursue blissful illusions in preference to truth. 10MM aficionados are particularly susceptible to becoming blinded by illusions. No, the FBI did not go with the .40 S&W because some of its cops could not withstand recoil of the 10MM. The .40 S&W was a superior law enforcement cartridge.

Hard to separate them out, no? Momentum, KE, and force are all directly related to each other along with bullet mass and bullet velocity.

Momentum = mv
KE = m ∫v dt = 1/2m(v^^2)
Force = m dv/dt

Pretty sure that's right. Been a few decades since I took dynamics. All three describe different attributes based on the same thing, the mass and velocity of a moving object (bullet).

Momentum is related to recoil and penetration ability.

KE is how much energy is available to do damage to whatever you're hitting.

Force is "knockdown" ability. Hard to figure dv/dt in practice so momentum is used a a proxy for force.

Like I said, been a while, but pretty sure that's right.

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Vegan by proxy.

Do Energy Foot-Pounds Matter? Yes or no? Why or why not?

Simple as that. I know it's probably an answer that I'll never receive because I'm asking on a forum filled with more opinions than factual evidence, but it's interesting to read folks opinions on the subject regardless.

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Shooting Comfort is bilateral.

It's an answer you'll never receive because you're asking for a yes or no answer to a question that depends on more information than just "do energy foot pounds matter."

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Vegan by proxy.

Several people have told you why energy matters. Instead of accepting the answers you have been given, you're bashing the forum as a place that isn't a place to get facts. Why go there? Doesn't seem very productive at all.

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Ban this man,
'89

Incorrect. I'm looking not only for yes or now, but how or why as well. So I'm perfectly open to an explanation, I just didn't want the thread to be derailed into an argument over silly stuff like folks of smaller stature being capable of shooting bigger bullets as well as larger folks, especially after we had already had a couple good posts which adequately covered that nonsense, or other such arguments regarding the FBI's decision to drop .40 in favor of 9mm. Yes, they're somewhat relevant, but they're not the point, and once folks get started on either subject, they don't want to stop.

Unfortunately, this is my issue with posting threads here. Everytime I do, folks go off on a tangent regarding a single facet of the discussion without ever returning to the topic itself, and when I attempt to steer the discussion back on topic everyone wants to argue with me about how the tangent is relevant to the main discussion and how the main topic is too difficult to answer, then bombard me with questions which were already answered in the first post, which they evidently only read the first paragraph of, hence the tangent.
If you cannot answer or otherwise don't want to answer, then don't. It's as simple as that. I don't expect everyone here to possess absolute knowledge on the subject, nor do I particularly mind if we never reach a definitive conclusion because I don't have unrealistic expectations of this thread. I would however, like it if we could stay on-topic rather than veer completely off course into a pointless, one-sided argument on controversial subjects which are doomed to result in the thread either being locked or prematurely abandoned because it can go no further.

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Shooting Comfort is bilateral.

Dirty Harry Callahan,

I feel that ENERGY FOOT POUNDS does matter, but with respect to shooting, I am (and most likely always will be) a dinosaur. I see self-defense much like hunting. In the event that I take a shot, I want the recipient of that shot to drop as quickly as possible.

In my perspective, bullet energy means momentum. For example, a 22 Long Rifle has a muzzle energy of 116 foot pounds, while a 357 Magnum (158gr) has a muzzle energy of roughly 530 foot pounds, and a 45 ACP has a muzzle energy of 355 foot pounds. Rightly or wrongly, I would like to believe that the more momentum that I can sling at a recipient will increase the chances of dropping the recipient. If my logic is off, I would love to see a welterweight boxer fight a heavyweight boxer!

Chances are extremely good that in a gunfight, the defender won't be able to deliver pinpoint accuracy, so you need a card up your sleeve, and in opinion, that card is momentum (bullet energy).

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Judge control not gun control!

p (momentum) = mv. What you'd be looking at is dp/dt on the target.

That said, disregarding outliers like .22 shorts, bullet placement is king. A .380 to the noggin beats a .44 mag to the love handle every time.

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SWCA #3356, SWHF#611

This sums up my thoughts on the topic pretty well.

Some folks argue that 9mm is enough and a more powerful caliber is overkill, but as a SOF buddy of mine said, "there's no such thing as overkill, there's just dead."

Did you take any physics in high skewl?

I converted my M&P 40c to .357 SIG because you never know when an extra 100 foot-pounds of muzzle energy might come in handy.

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What, me worry?

Yes, kinetic energy matters a lot, but only when when velocity and projectile shape and mass are such to allow appropriate penetration.

Imagine you are walking along the sidewalk and you are hit by a loaded dump truck going one mile per hour. Even at one MPH a loaded truck has big kinetic energy, but you just bounce off and walk away. Why? Because the velocity and shape do not allow penetration.

On the other hand, neutrinos, which travel at nearly the speed of light but have nearly no mass, pass through your body many times every second. You didn't feel them, did you?

To be effective, bullets need kinetic energy with both significant velocity and significant mass, and they need an appropriate shape.

Momentum, on the other hand, is a red herring. The momentum imparted to the target is less than the momentum imparted to your body. Did that shot you fired knock you down? If not, then the momentum will not knock down the person receiving the shot.

Yes, energy matters, but you can't draw a correlation between between energy and shots that stop a living thing because there are:

1) Other ballistic variables

2) Way too many different shooting situations and targets

Even if you just count C.O.M. shots at head-on human targets (just a ferinstance to narrow it down) you will still get different results because there are WAY too many variables.

Someone told the story about the woman who killed a Grizzly with a .22L rifle. I AM NOT going to hunt Grizzly with a .22L rifle. I want something with a bigger heavier bullet of the proper type, moving at a good rate, which incidentally, will have more energy.

I'm not going to choose a gun for any purpose solely on it's energy, but more on it's reputation and results of testing. I could easily say, "If more energy is better, I'll carry a .50 Desert Eagle" but I much prefer something in the 9mm to .40 S&W range.

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"He was kinda funny lookin'"

No, never.

In fact, I never attended High Skewl at all, unfortunately. How was it? I hear their Language Arts classes were extremely poor, but they made up for it with their top-notch Smart Aleck classes. Which in spite of being a worthless course in the academic sense, supposedly proves invaluable to those who can only appear intelligent by way of denigrated the intelligence of others.

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Shooting Comfort is bilateral.

My very humble opinion is that what matters most is that you hit your target. A miss with 45-70 handgun just doesn't get the job done. If that handgun is a 22LR, so be it.

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Foster Positivity.

if an individual is hunting Cape Buffalo then YES energy - foot pounds / bullet mass matter a whole LOT, everything else is secondary. I think carrying a 400 Nitro express would be adequate in that scenario...For 2 legged perps not so much. For defense in the common application of that term there is a compromise one should ask oneself. Controllability, F/U shots & speed for same would require consideration for a caliber that is sufficient to penetrate adequately & fairly good ability to maintain on target between shots. I prefer .40 or .45 for this. Enough mass, enough penetration. As always accuracy is king.

There is no CNS 'shock' or massive permanent tissue displacement in these conventional pistol calibers. Anything traveling at 2000 FPS or better & carrying a payload upwards to 400 grains or more is a whole nother level., at that level lots of things happen that will never happen in a conventional defense pistol caliber.

The initial physics answer is of course it matters. The more the better. Follow up question that needs to be answered is how much does it matter? In hand gun calibers the energy at the muzzle or at the target is only 1 variable. Many other things are also involved. Shape of bullet, hollow point or soft point? Expansion, shot placement.
To be short..the more energy the better. It just may not make much difference to the final outcome.
Shot placement is the major factor to disabling or killing a target. When a shot is very accurate or well placed then velocity, muzzle energy, bullet weight are all lesser factors. (The .22 to the temple scenario)
If that variable/ factor is not fatal instantly the more the other variables become important. So in a pareto graph of what matters most to kill a target
shot placement is a towering #1 followed by X,Y and Z.

But the question is does it matter?
The answer really is if the pareto effects come down to muzzle energy being the "next factor" that causes death / incapacitation then it matters.
The 2nd most critical factor to shot placement of initial shot is for the follow up shots. The ease of getting subsequent shots on target. If you can't make a fatal 1st shout then the follow up shot placement becomes very important
Since shot placement is the most significant factor, both 1st shot and subsequent then you could argue that Muzzle energy isn't very important at all in a real life scenario.

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John 1:17
NRA Life Benefactor

Well, ya shoulda. They have free ones, run by the gubmint,
ya know?

Aside from being tetchy about the subject, if you had taken
basic physics, you'd know energy=ability to do work.

Projectiles are imbued with energy by acceleration to a
particular velocity, said velocity giving more and more
energy (ability to do WORK). Faster and heavier, more
energy...lighter & slower, less work.

Wanna carry a .177 CO2 pistol for defense?

Work and Energy

Pretty much outdated junk, from 1989, in the pure-theory
camp of Fackler. Not sure the context of "peer review",
as used here. Peer-review occurs at prior to initial publication
of a scientific study. The cited work is not a study, but an
expression of author's feelings about Fackler's work;
essentially, it's an op-ed.

Fackler, and his followers, seem to have grave concerns
with anyone entering *his* field of authority, let alone having
an alternate approach to the subject matter. Note the final
third or so of the text is comprised of attacks on Marshall &
Sanow's work.

Take your pick. Pure theoretical conjecture, or examination
of actual shootings of subjects in "real life". I know what holds
more water for me.

Once we have a definitive consensus on muzzle energy, we can talk about sectional density. Changing my thinking a bit, so far as woods anyway.

147g 9mm = 230g 45acp.

Shot placement is king. I have watched prairie dogs crawl down their burrow by dragging themselves with only their front paws when shot with a 25-06 at 50 yards.

I have also seen prairie dogs tip over dead right there when shot with a 22 LR at 175 yards. The sun was behind me, I saw the bullet's flight in my scope, bullet hit the target, and the prairie dog tipped over like a bowling pin.

Prairie dogs aren't humans, but massive tissue damage doesn't always stop a person or animal. In a self defense situation, one accurate shot with a 22 LR trumps a flesh wound with a 44 magnum or 45 ACP. The chance to make a second effective shot is greater with a 22 LR than a 44 magnum or 45 ACP, at least you will still have your hearing.

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S&WHF 366

No. It's a comparative index of nebulous value.

Penetration is a function of momentum.

E = MC squared...so on a sunny day i can use a smaller bullet ..sorry to diverge

This issue has come up again and again. Another one of those zombie threads that apparently surface when there's nothing compelling on TV and you're out of new videos.

I expect a search would turn up about the same set of opinions already expressed plus a few more. A lawyer would pipe up with "asked and answered".

This is the place where I disagree with the internet gurus and so-called experts.

Once the rounds start flying and the target gets their adrenaline dump, they'll be moving very quickly and erratically; the first shot has the best chance of landing and thus should be the one you're counting on to do the job. Anything after that is jelly.

Might not be the prevailing expert opinion... it's just mine.

EDIT to add: The rest of the post is very true. Far too many variables.

A very simple question: how much of what will you need to accomplish an intended task. A corollary: at what point will you experience diminishing returns.

The .300 WM has impressive kinetic energy (ballistic tables) vis-a-vis the 150 year old .45/70 Gov't. If I had to go into thick stuff after a mean griz, I'd take a Model 1895 loaded with modern .45/70 ammo every single time.

We would have a much more clearly defined picture of energy requirements if we were to grasp the process of incapacity. Without CNS destruction, a good guy must rely upon reducing a bad guy's blood pressure to zero while avoiding taking a bad guy's rounds. Nothing living remains in that condition absent topside oxygenated blood flow. The potentially fatal problem for good guys is it can take a very long time to deny a dirt bag's grey matter of oxygenated blood flow, all the while he'll remain a very deadly threat.

Cops do not have the option of avoidance. They have to confront and possibly engage. Those of us who are retired cops and those who are not sworn cops, shouldn't engage unless no other option exists.

Two rules that will assure remaining vertical:

1. Avoid, avoid, and avoid some more to include hightailing it outta a potentially deadly encounter. It's much more wise to be a live witness than a dead hero.

2. If 1 is not an option, do not get shot. That means you'll have to get out of a bad guy's sight picture.

Always remember that a gunfight involves a bad guy who wants to reduce a good guy to evidence of murder and his corpse scheduled for autopsy the following morning.

Energy matters but only if the bullet does work. This gets debated all the time, but if one thinks that there is a huge diff between a bullet reaching say 65cal & penetrating 15"+, well there just isn't. Adding 100ft# isn't going to knock anything down or over or whatever the magic some think it does. Look at good 9mm 124gr+P vs 180/40 or 230/45, all close enough in ME to not matter. What the larger caliber bullets do is give more matl for expansion & wt to drive the bullet deeper.
For those that do not shoot a lot, good 9mm jhp make sense. Recoil management isn't something that comes with the badge, but 1000s of rds in practice. The avg LEO or ccw isnt going to ever fire the amount of rds needed to learn to manage heavier recoiling guns. Throw in extra rds & smaller guns, bonus.

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NRA Cert. Inst. IDPA CSO

I think the issue is the first shot is not likely to land in the hurry of the situation for most. Fast follow up shots may just be what is needed.

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NRA Cert. Inst. IDPA CSO

Mostly it is a function of the bullet design. FMJ vs JHP, momentum is second to that. A 115gr FMJ 9mm @ 1200fps as a pretty low momentum of 138 but will penetrate quite a bit in tissue. A 230gr HST @ 850fps has a momentum of 195 but more than likely stops before that 9mm ball round.

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NRA Cert. Inst. IDPA CSO