The 9mm vs 40 S&W vs 45 ACP debate has been raging for a long time. I can’t solve it for you, but I can give you the information you need to make an informed decision. But we need to jettison some pseudo-science first.
Kinetic Energy does not matter.
Seriously.
It has exactly zero effect of a bullet’s deadliness.
Don’t believe me?
A 490 grain Broad-head arrow traveling at 225 Feet Per Second (FPS) has a kinetic energy of 55 ft-lbs. A 1 pound gel filled bag launched at 60 FPS has a Kinetic Energy of 55 ft-lbs.
Exact same energy, but which is more lethal?
Its very simple and easy to understand how an attacker can be incapacitated. But it’s not with some mythical force called “stopping power” or “knock down power”. Consider this: Can you measure “Stopping Power” or “Knock Down Power”?
Seriously, how many “Stopping Powers” or “Knock Down Powers” does a 45 ACP have? How about a 9mm or 40 S&W?
I’m not the only with this opinion either. The FBI switched back to 9mm from 40 S&W a couple years back. They released a report justifying the switch which is well worth a read.
Studies of “stopping power” are irrelevant because no one has ever been able to define how much power, force, or kinetic energy, in and of itself, is required to effectively stop a violent and determined adversary quickly, and even the largest of handgun calibers are not capable of delivering such force. Handgun stopping power is simply a myth.
(Bold emphasis theirs, red emphasis mine.)
It doesn’t matter if it’s 9mm, 40 S&W, or 45 ACP; they all do damage the same way. So before I get into comparing and contrasting 9mm vs 40 S&W vs 45 ACP, lets spend a minute talking about how bullets ACTUALLY do their damage.
Wound Ballistics Basics
(try saying that five times fast)
Anyway…
According to the FBI report Handgun Wounding Factors and Effectiveness, there are only two ways a bullet can do damage:
#1. Permanent Cavity. (The tissue the bullet touches directly, which it crushes into oblivion. Basically the hole it leaves.)
#2. Temporary cavity. (Basically the tissue the bullet damages, but does not touch. Read my “Stopping Power” and The Simple Truth of Terminal Ballistics article for more details.)
Here’s the bad news: most handgun bullets can only create a damaging permanent cavity (hole). Rifle bullets can create a damaging temporary cavity and are far more deadly. But unless you have a rifle or very powerful handgun, don’t even worry about a damaging temporary cavity. (there are a few exceptions, which we will discuss lower down)
Pistol bullets only poke holes.
That’s it.
Here’s the FBI on the matter:
Handgun stopping power is simply a myth
The single most important factor in effectively wounding a human target is to have penetration to a scientifically valid depth (FBI uses 12” – 18”)
Yeah it’s a great line about a 44’s power. But Hollywood got something about guns wrong… Again. Surprise, surprise.
Pistol bullets – even large ones like the .44 Magnum – literally CAN’T knock a person off their feet. Smaller ones like 9mm and 40 S&W don’t even have a prayer of doing it.
They just can’t.
To inject some science into that statement, let’s look at the first law of thermodynamics “For every action, there is an equal and opposite reaction.” That means that all the force the bad guy feels is also felt by the shooter (in the form of recoil).
Therefore, If a bullet can knock the bad guy down, it would also knock the shooter down. (though the forces might feel different because the weight of the gun reduces the force the shooter feels.)
Even 45 ACP bullets can’t knock someone off their feet. If you break major bones, they may be unable to continue standing and then fall down. But they won’t be “knocked off their feet”. Worse, they might not be stopped, or even slowed down.
Don’t believe me?
Two suggestions: watch a video of someone shooting 45 ACP into a block of ballistics gel. The block of gel weighs around 20 pounds, and the 45 ACP can’t make it go flying. If it can’t move a ~20 pound block of gel, what makes you think it can “knock down” a 150-300lb man?
Second, I suggest reading this article recounting a police officer’s encounter with a bad guy: Why One cop Carries 145 Rounds of Ammo on the Job.
No really, go read it.
I’ll wait here.
…
…
The officer’s pistol was a Glock 21 chambered in 45 ACP and the officer himself was:
“A master firearms instructor and a sniper on his department’s Tactical Intervention Unit, “I was confident at least some of them were hitting him, but he wasn’t even close to slowing down,” (emphasis added)
And this one too:
“I thought I was hitting him, but with shots going through his clothing it was hard to tell for sure. This much was certain: he kept moving and kept shooting, trying his damnedest to kill me.” In this free-for-all, the assailant had, in fact, been struck 14 times.” (emphasis added)
Here’s the clincher:
“no evidence of drugs or alcohol was found in his system.“
Pistol bullets can only poke holes; they can’t knock people down.
(and don’t forget, that’s the FBI’s professional opinion after untold hours of research and testing)
Movies have been getting this wrong for years. A western draw is a perfect example. The slower shooter always stops like he’s struck by a bolt of lightning. For the most part, that’s pure Hollywood fantasy. (unless the bullet hits either the brain or spinal cord)
So What Does it Take to Stop a Bad Guy?
Answer: You have to poke the holes in the right places.
In the 9mm vs 40 vs 45 debate, you can’t forget this simple fact:
The only way to instantly incapacitate an attacker is to destroy or disable the brain. If you can hit the brain, it’s lights out. (The officer ended the gunfight with a few shots to the assailant’s head.) However, the head is a small and easily missed target.
Because the head is a small target, conventional wisdom says aim for high center of mass.
For once, conventional wisdom isn’t completely wrong.
You need to disable the brain to force an attacker to stop. The only real way to do that (other than hitting the head or spinal cord) is by poking enough holes in arteries that they blackout from blood loss.
There’s a whole host of arteries and veins – not to mention the heart – that are protected by the rib cage. Hit enough of them, and their blood pressure will lower to the point of forcing unconsciousness. However, even if you put a bullet through the heart they will still have 6-10 seconds of consciousness left.
6-10 Seconds in a LOT of time in a gunfight.
It’s plenty of time for them to return fire, attack you with a knife, or swing a baseball bat with bone breaking force. To make them stop, you need to disable the brain. To do that without hitting it directly, you need to hit large concentrations of blood bearing organs and/or arteries.
The best place to do that is high center of mass.
However, It requires proper shot placement to incapacitate ANY bad guy. Hitting the bad guy in the pinky finger with a 500 S&W Magnum is less effective than hitting them in the head with a 22LR.
To back up these claims, I’ll quote the FBI justification for returning to 9mm:
Shots to the Central Nervous System (CNS) at the level of the cervical spine (neck) or above, are the only means to reliably cause immediate incapacitation. In this case, any of the calibers commonly used in law enforcement, regardless of expansion, would suffice for obvious reasons. Other than shots to the CNS, the most reliable means for affecting rapid incapacitation is by placing shots to large vital organs thus causing rapid blood loss. Simply stated, shot placement is the most critical component to achieving either method of incapacitation.
(emphasis mine)
I’m not just making this stuff up.
Now that we know how to stop a Bad Guy, back to the debate…
In my opinion, 9mm vs 40 S&W vs 45 ACP doesn’t matter too much because they all poke holes around the same size. Yeah I know that sounds silly, but it’s true. The FBI Justificaiton for going back to 9mm backs this fact up again.
There is little to no noticeable difference in the wound tracks between premium line law Auto enforcement projectiles from 9mm Luger through the .45 Auto
As further proof, check out the picture below.
Picture borrowed from The best choice for Self Defense Ammo – Pistol Ammo
Those are Winchester T-series hollowpoint bullets after expansion. They are commonly agreed as one of the best jacketed hollow point bullets around.
Notice how close the expansion is.
The difference between the 9mm and the 45 ACP is only .12 inches. Basically one eighth of an inch. The 40 S&W splits the difference exactly.
Now, lets say you were in a self defense scenario and hit the bad guy. Good for you. But lets say the bullet missed something vital, but only missed it by a tiny little bit.
If you were shooting a 45 ACP that landed in the exact same place as a 9mm, you’d only be half the diameter – or 0.060 of an inch – closer to the vital zone than a 9mm.
1/16 of one inch. That how much closer you’d be with a 45 ACP vs a 9mm.
With a 40 S&W, you’d be 0.03 of an inch closer than a 9mm. That’s only 1/32 of an inch (less than a millimeter) in a 9mm vs 40 S&W.
Yes I know, that’s only one type of bullet. So how about larger sample size?
Lucky Gunner did an extensive ammo test with over 100 different types of self defense hollow points. They listed the raw data along with gel pictures and video. I added the average expansion numbers for 9mm, 40 S&W, and 45 ACP and here’s what the number’s say.
- 9mm Average Diameter: ~.5
- 40 Average Diameter ~ .59
- .45 Average Diameter ~ .58
The total average difference is actually LESS than the difference between the hollowpoints pictured above. If you count expansions as being closer to a vital organ/artery (half the diameter.) then the difference is 0.060 with the picture vs a 0.045 spread with Lucky Gunner Average. To put that in perspective, that’s less than 3/64 of an inch difference between the largest and smallest according to the Lucky Gunner average.
The individual bullet makes more difference than the cartridge.
Now look at this ballistic gel gif and how much everything is getting blown around.
Do you really think that tiny little size difference will matter that much?
I mean really?
In a certain sense it MUST matter because sometimes that TINY difference will occasionally allow you to hit something vital you would’ve otherwise missed…. assuming you shoot just as well with the larger caliber (and most people don’t).
I would give a TINY edge to larger calibers simply because their large diameter does occasionally make a difference. But I would only give them A TINY edge.
Follow the logic:
- If poking holes is about all pistol bullets can do.
- And if 9mm, 40 S&W and 45 ACP all poke holes around the same size
- then they should have about the same effectiveness. (with a very slight edge to the larger bullets)
Here’s the data to back up that logic:
An Alternative Look at Handgun Stopping Power.
I pulled some relevant data and compressed it to a single table:
| 9mm | 40 S&W | 45 ACP | |
|---|---|---|---|
| Average number of rounds until incapacitation | 2.45 | 2.36 | 2.08 |
| % of people who were not incapacitated | 13% | 13% | 14% |
| Percent actually incapacitated by one shot (torso or head hit) | 47% | 52% | 51% |
A few things to point out:
- All of our cartridges took more than 2 shots on average to stop someone. (though the 45 ACP was close to needing only 2.)
- Their failure to stop rates were all within 1%.
- Their one shot incapacitation rate was within 4%.
So if you compare the actual 9mm vs 40 S&W vs 45 ACP “stopping power” (incapacitation) numbers, it boils down to a measly 4%. Like I said, I’d only give larger bullets a TINY edge.
It’s probably closer than that because of the effect being shot sometimes has on people. Again from the same article:
“In a certain (fairly high) percentage of shootings, people stop their aggressive actions after being hit with one round regardless of caliber or shot placement. These people are likely NOT physically incapacitated by the bullet. They just don’t want to be shot anymore and give up! Call it a psychological stop if you will. Any bullet or caliber combination will likely yield similar results in those cases.“
So in most self defense scenarios, a 22LR is just as effective for making bad guy give up as a 45 ACP. I’m not recommending you carry a 22LR, but remember that almost any gun will do it most of the time….
I’d recommend 9mm as a minimum, because smaller bullets don’t really have the penetration and expansion 9mm has. One or the other separately, but usually not both. However, I’ve recommended a few people carry .22LR because they couldn’t hit the broad side of a barn with anything else.
EDIT: I recently wrote an article titled “How Many Rounds Do I Need For Concealed Carry?” I included a study about police officer hit rates and the FBI’s opinion on 9mm vs 40 and accuracy. That resulted in some interesting numbers on how many rounds it takes from each cartridge to stop an attacker. So 9 vs 40 vs 45, which do you think took the most rounds? The answer might surprise you…
9mm vs 40 S&W vs 45 ACP Conclusion
I don’t really care which one you use as long as you are accurate with it. They all poke around the same size hole and have around the same effectiveness. Therefore, what matters is Where you poke that hole.
Hitting someone in the pinky finger with a .500 S&W Magnum is less effective than hitting the head with a 22 LR. You’ll see me say this all the time: NOTHING trumps shot placement.
Nothing ever has, nothing ever will.
The famous western lawman Wyatt Earp was renowned for his skill as a gunfighter. He has this to say about accuracy.
“Fast is fine, But accuracy is final. You must learn to be slow in a hurry.”
Wyatt Earp had gunfights with faster men many times, but he always came out on top. Why? If you read more about him you’ll discover he always took time to properly align his sights before pulling the trigger. Even at a distance of only 5-10 feet.
I found an interview with Wyatt Earp if you’d like to read his thoughts on gun fighting. It’s well worth a read but spoiler alert: his theme is basically this:
NOTHING trumps shot placement.
I’ve said it before: you can’t miss fast enough to win a gunfight or fill a hunting tag.
That statement is borne out in my carry choice. I carry a 9mm for two reasons. Reason #1 is because I shoot 9mm better than 40 S&W or 45 ACP. Reason #2 is because 9mm ammo is cheaper than 40 S&W or 45 ACP, so I can practice more for the same money.
I would recommend you carry whichever you shoot the best. It doesn’t matter to me if it’s 9mm, 40 S&W or 45 ACP.
What matters to me are rounds on target.
If you don’t have a pistol yet and/or are trying to decide what caliber to carry, I would recommend firing them all and then deciding which you shoot the best and are most comfortable with. If you have gun loving buddies, you could ask to try their pistols out. Failing that, rent some at a local range.
Fire them all, and pick the one you’ll shoot the best. Remember, they all poke about the same size hole. So pick the one you shoot the best or that you feel most comfortable with. Again, I don’t really care about 9mm vs 40 S&W vs 45 ACP.
It doesn’t matter to me.
What DOES matter in a life and death situation is accuracy.
I carry a 9mm because I shoot it better than the 40 S&W or the 45 ACP. Pick the cartridge you shoot the best, then spend a lot of time practicing. That’s what will make the difference.
As an addendum, the FBI justification for going back to 9mm has this to say about the accuracy of various cartridges:
The majority of FBI shooters are both FASTER in shot strings fired and more ACCURATE with shooting a 9mm Luger vs shooting a .40 S&W (similar sized weapons)
And there’s one more thing….
How to “Cheat” the Normal Rules of Handgun Wound Ballistics
The winning formula for hunting or combat is this: Great accuracy + Great bullets = Win. This section isn’t about cartridges, it’s about bullets.
I’m a firm believer that “If you find yourself in a fair fight, your tactics Suck“.
That’s why I don’t carry “fair” ammo. And by fair ammo, I mean the same Jacketed hollow point bullets used by 95%+ of the people who carry concealed.
There’s better options these days.
The vast majority of handgun bullets can only poke holes. But there’s a few extremely well designed bullets that can do more. Sometimes a LOT more.
My current carry ammo is the 9mm Polycase ARX. It was recently picked up by Ruger and is now usually sold as the Ruger ARX. I intend on changing to the Lehigh Defense Extreme Defender (NOT the Extreme Penetrator) when my budget allows.
I won’t into the technical details, but they allow you create a MUCH larger wound that is possible with conventional hollowpoint bullets. Additionally, since they don’t rely on expansion there’s no real possibility of them failing to do their job.
The Military Arms Channel did a great video on the Lehigh Extreme Defender’s performance. The comparison was with the Federal HST.
So, my solution to the whole 9mm vs 40 S&W vs 45 ACP debate was to carry a 9mm because it’s what I shoot the best. Then, I picked ammo that allows my 9mm to create a wound larger than a .45 ACP hollowpoint.
That’s what I call a win.
If you find yourself in a fair fight your tactics suck. So don’t get caught in a fair fight.
I use “unfair” ammo, but NOT because I want to kill someone. That’s the LAST thing I want to do. I carry that ammo because IF I am ever attacked, I want to survive. I pray the only time I ever draw my carry pistol is at the range to practice. But if I’m forced to defend myself or others, I want the odds stacked in my favor.
So wherever you fall in the 9mm vs 40 S&W vs 45 ACP debate, remember one thing. The winning formula isn’t using cartridge ABC or XYZ. The winning formula is Great Accuracy + Great Bullets = Win.
I have an aging .45 and decided on a new pistol was contemplating another .45 but licensing would have been somewhat tricky so decided on .40 S&W Glock 35 Gen 4. This I did 26.10.2016, paid up front and licensing in progress. Had I only read your article, which to me makes sense, I would have gone for a 9mm.
Regards
If you really want a 9mm instead, you could do a conversion. You’ll need to change the Barrel, magazines, recoil spring assembly, striker, extractor assembly, and ejector (which means the trigger mechanism housing), but it’s doable. Of course, That’s a fair few parts an G34 barrel alone will run you around $150.
Just a thought.
You are forgetting penetrating distance. The FBI has standards for that which includes the “shootee” wearing thick clothes such as parkas or tough leather jackets. I read many NATO personnel claimed that the 9mm was marginal and wanted something stronger. Can a 40 break the rib cage and hit the heart?
A 40 can do it easily, but so can a 9mm or 45. Further, all three can do it through the FBI “heavy clothing” tests.
If you read the FBI’s Justification for going back to 9mm, you’ll notice these three paragraphs.
And
And also
As for NATO issues with penetration, I haven’t seen that anywhere and all the test I’ve seen indicate that FMJ projectiles that NATO uses usually result in extreme penetration because they are non-expanding. (which makes perfect sense)
If by “NATO personnel claimed that the 9mm was marginal and wanted something stronger” you mean it’s ability to wound/stop the enemy, then you are absolutely right. ALL pistol bullets (unless you have a fairly powerful magnum) stop people pretty poorly. The bag guy not stopping after 14 rounds of 45 ACP hollowpoints is only one proof of this. There’s a LOT out there if you do a Google search.
Yes the 9mm is marginal, but so are the 40 and the 45. It’s why SWAT ditched sub-guns like the MP5 in favor of 5.56 rifles and shotguns. That said, any pistol is better than nothing, which is why I carry.
Excellent discussions… keep in mind that organizations that have to arm many people, such as the FBI, they have to use statistics to base their recommendations on (e.g., the 20-30% hit rate). But each individual is different as is each weapon. I’m pretty darned good with the Springfield .45ACP… not so much with the Ruger 9mm. So the discussion comes back to… if the goal is to stop the adversary from being an adversary then you (assuming you aren’t provided the weapon by an organization required to arm a lot of people) need to find out what weapon and caliber works best for you. If you’re hit rate is higher with the .45 then you might not need to fling as much lead to get the job done. The data sure seems to show that the ammo isn’t a major factor but hitting your target for sure is.
On that note, if you’re “flinging lead” please get to the range more. Practice saves lives.
So, find a range that rents guns or friends that shoot and see what works for you.
And youre right… “stopping power” is just a phrase not a data point and has no real meaning.
An arrow’s lethality isn’t based on kinetic energy, never was. It is purely based on cutting…Nothing else. A sharp broadhead that does not hit major bone will pas entirely through on most game. Its kinetic energy is meaningless and has absolutely nothing to do with its penetration on game. A broadhead must be sharp in order to cut organs, not push them aside which it would do if it is dull. The rest is based on bleeding and it is often far quicker than a well placed bullet to achieve its end. I’ve seen it and experienced it personally on large game.
For a bullet shot placement is crucial. However for a bullet kinetic energy is one of the most important factors as is bullet construction and good sectional density.
I agree with you that accuracy is primordial but not that kinetic energy is of no importance. A bullet is tiny compared to an arrow. If an arrow weren’t equipped with a very sharp broadhead but instead with a field point, it would still pass through but may not be lethal or may cause an agonizing death over a period of days.
Well first,
The pics of the bullets you called federal hst tactical shown is wrong ! Really bad when your suppose to have all this information about which caliber is best and you don’t know the difference between a federal hst and a Winchester t series.
Yes the bullets shown are t series. Yes wile all are close after fully mushrooming from the start of when the bullet starts to expand and travels 5 to 6 inches is much larger . So during this 5 to 6 inches the 45 being largest will cut a much bigger path than the 9 or 40.
I do agree shoot with what you can handle and shoot more accurately. And use the best ammo you can get. The lehigh extreme defender is a great bullet. And as you say it in 9mm leaves a larger wound cavity that a 45, that’s 45 hollow point. Now tell me the 45 with the extreme defender will not make a larger would cavity that the 9mm using the same bullet? If you can handle the 40 or 45 use them.
Fixed. Sorry for the mix-up and thanks for pointing it out. 🙂 In hindsight, I don’t know how I did that. Both the HST and T-series are very distinctive in how they look after expansion.
I love science. But damn I love .45 … I was an MP in the USMC-R. Never set a range record, but literally tied all of them except for boot camp; where a FREEZING cold pre-qual day (with a field jacket on) caused my 300 yd rapid set to all be off … but OBVIOUSLY it was my field jacket. PMI FORCED me to adjust my sights, and I subsequently missed in the exact direction he forced me to adjust it to. Got a 236 / 250 back when that was the scoring (I hear it’s diff now)… and would have beat the record for who knows how long. Instead, yeah, expert, but who cares.
I fucking LOVED the Glock 21. TONS of big bullets. Low bore axis meant (as I experience it) nominal flip and the rest straight back. My 3-round rapid at 10 feet was ridiculous back when I was doing it.
The 45 ACP never felt like “recoil I could handle bro.” It felt like LESS RECOIL. Why? Lower velocity rounds, might have translated to it having less foot-pound… ? Or maybe because the grip is huge (I have big hands).
It’s just my favorite pistole I’d ever used. Forget the Beretta 92FS. Had a Sig 229 (.40 cal) … 12.5 pound trigger for the first (and potentially most important round) is absolutely a cool looking pistol. But, it’s not great to tear down. The double action feature isn’t great.
9mm are just … whatever. Couldn’t get an HK-91, settled for a SAR-8 … have a 3 round group from 200 yds STANDING (hasty sling for support) that’s 1.5″ … iron sights.
First scope I ever used with a rifle (didn’t occur for another 2 years … when I got my bolt-action dream. A 700 PSS, H Bar in 7.62×51 of course… which is absolutely monogamous with the Leupold Mk iv M8 (and took quite some time from which to acclimate).
Had a Mini-30 (7.62×39) … HATED… LOATHED that I had to use a bore cleaner past the crown of the barrel; YES, I know it’s not — THAT Accurate — but I despised that cleaning it required running a metal brush through the crown of the barrel.
It’s like, getting a NICE SKS; Same round. Beautiful design. Bigger magazine.
And that’s all the yammering I feel like doing. I’m sorry to anyone who found this to be overly self “adulating.” I am just sitting in bed farting, watching people on youtube. Nothing special. But weapons are awesome fun when learning to be accurate. And I will keep that 3 round standing group from the SAR-8 for the rest of my life. UNDER an MOA, off hand,
I’m HAPPY to say I’ve never shot anyone. And I politely believe there’s room for more variables in the utility of a .45 … ESPECIALLY, the Glock 21. Still, I appreciated your logic, and if you’re right (i’ll look for others which also undermine my potential ‘confirmation bias.’) If I’m wrong, I look forward to saying, “I discarded a belief I held for 20 years.” I’d rather be right than dogmatic. For now, the ‘evidence’ doesn’t overwhelm. (My apologies if I’ve annoyed anyone or sound grandiose; just reliving years past.)
By far the best article i have read on the subject, thank you.
I live in NYS and max cap in hand gun is 10 rounds ONLY.
I’m thinking if I am limited to only 10 rounds, I might as well get the biggest bullet like the 45, thinking that it has a little better terminal ballistics in regard to “stopping power” than the 9mm. I mean, more rounds for 9mm is probably the biggest advantage but I live in a state that drastically limits ammo cap and doesn’t matter if it’s a 22LR, I’m still limited to 10!
Now, with this in mind would you guys still recommend 9mm over 45acp? Or that it’s still marginal difference so that it doesn’t matter?
To me, I or my wife can shot the 45 the same as 9. No difference in speed or accurately.
Please help. (For primarily home defense, especially my wife)
If you’re limited to 10 rounds max and truly shoot .45 just as well as 9mm, then the bigger hole always wins. I like 9mm because so many people shoot it better (including me) and you get high capacity. But since neither of those advantages apply to you I’d opt for the bigger hole. 9mm ammo will be cheaper for practice though.
Abe,
Thanks. That’s what I thought.
I respect your opinion, but like most, I believe you look at it the wrong way. There is a reason the military asked for its new pistol to also have a larger than 9mm caliber available. The Sig won out, but caliber as yet to be released, as the Sig that won is both a 40 and a 9 mm. In regards to your arrow vs gel bag, this is a very skewed and unrealistic argument. An arrow is designed to go through while ‘cutting’ as much as possible. The bag was not made to enter a body. Stopping power is measurable. The easiest way is to hang a target from a tree, shoot it and measure the distance it moves back vs other rounds.(I know this is not exact but is an easy visual you can do in your back yard). Outside of rifle rounds, non are going to knock you down. But imagine your a beat cop and someone happens to be wearing body armor(which is very common over seas, getting more common, although still unusual here) then the extra thump would come into play. Also, if you are shooting for home defense and are carrying a very good hollow point, if that hollow point does not go through the body, then you have dumped all that energy into the body and it again comes into play. A FMJ with transfer much less energy into a body than the G2 RIP round. This is why rubber bullets are so effective and hurt so much, they transfer 100% of their energy into what they hit. So, in summation, stopping power is real, but the key is the amount transferred into the target itself.
I have to respectfully disagree.
When the FBI went back to 9mm from 40, they released a report justifying the change. One of the bullet points in the beginning says:
and later in the article:
Setting that aside though, lets use your suggestion of hanging things from a tree in your backyard. I’m a lightweight at ~150 pounds right now. If you hung a 150lb sandbag from a tree and shot it with a pistol bullet, I don’t think it would move much. It can’t because of physics. A pistol bullet just doesn’t have enough mass to make 150lbs move very much. A Little yes, but not much.
I respectfully disagree with both Trey and Abe. 🙂
Abe’s assertion: Newtonian physics causes “equal forces to shooter and target”:
Sure – we can make them the same
• Use an electric primer
• Connect the bullet to a 6″ x 6″ steel plate on the shooters chest
• Stand with his feet close together, his head over his pelvis. His pelvis over his feet.
Now tell me how it feels in comparison to the other guy if he’s shot 2 feet away in the center of an identical 6×6 plate.
Trey:
Your point — seems to compare the impact of bullets against hard body armor for the subject, and inferring the energy pulse (which doesn’t penetrate in which case, there is no instant pulse, there is a pulse-duration in which the bullet is slowing as it penetrates…and you physiologically react as though your hand touched the oven.
In contrast, the shooter’s energy is dissipated by the operation of the weapon, potentially features that redirect the gas to mitigate the forces, the shooters stance, the fact that they connect the weapon to the most piston like structures in our body which are the lightest – and don’t manipulate the orientation of our legs directly (like a gun shot from your leg would… but rather, through your arm, which absorbs – before it’d transfer to your center of mass, requiring you adjust your stance (maybe not with an air soft or a pellet gun, but I hear those .22LR’s’ll knock you back a bit. 🙂
Anyway, you guys get what I mean… and if you think there’s any validity, cool. If not, my apologies for butting my newbie ass in. 🙂
Truman, you make a good point and there’s something I left out which explains the obvious discrepancy between what the shooter feels and what the target feels.
The mitigating factor is the weight of the gun. If you go to a recoil calculator and input the specifications for the a 9mm load (for instance) then vary the weights, you’ll see it’s easy to make the recoil of the 9mm significantly more (or less) because the weight of the pistol attenuates the recoil impulse before you ever feel it.
So yes, they would absolutely *feel* different between shooter and target; but the physics stays the same.
However, the total force (as a technical physics point) imparted to the shooter + the gun must exactly equal the force imparted to the target (minus air resistance between shooter and target) or you have violated the first law of thermodynamics.
While I was managing the gun shop, a fellow came in with a featherweight Double Tap Derringer in 45 ACP that had fired both rounds at the same time. (his fault) He said it hurt like hell and the recoil actually cut into his hand. Without the mitigating weight fo the firearm, recoil would be very painful. However, the total energy of the system (in a physics sense) must stay the same.
For more “real world” proof, watch a few videos of rounds being shot into ballistic gel. Even the 308 doesn’t make a block of gel go flying, though it might jump a little. The block of gel weighs a LOT less than the average man.
I’ll start off by saying that having shot all three calibers for most of my 20 yr shooting career, I have my preferences. I like the .45ACP a lot. Mostly because it is the chambering for guns I shoot well (the Glock 21, and M1911) and because I like the confidence that gives me. That said, I carry a .40S&W Glock 23, and that round is one that I also shoot well and feel confident carrying. I shoot a 9mm well enough, but my aversion to the cartridge stems more from military experience, which restricted my ammo choice to only ball ammo. I will disagree with your assertion that kinetic energy doesn’t matter. Kinetic energy does matter, it’s just that it’s only part of the equation. Your example clearly shows that 55 ft-lbs of energy is enough to kill (in the case of the arrow) or stop (in the case of the gel bag). Hell, I can probably generate more energy with a punch or kick. Kinetic energy alone is a useless consideration, I agree, but how that kinetic energy is transferred to the target is important. The .45ACP is a bigger bullet, with more mass, and lower speed. It dumps more of it’s energy into the target in a shorter time frame than the 9mm, which goes faster and is lighter and smaller. You are absolutely correct that bullet choice and shot placement are the most important factors in a gunfight. Famed US Navy SeAL Chris Kyle said in his book, that he switched from carrying a .45 to a 9mm because he found that he was able to achieve better shot placement with the 9mm, and that was more important to him. I felt that it was necessary to state this stuff, as I do agree with you, but it seems we arrived at our conclusions by different means. I tend to chose bigger bullets because of the confidence I get from those rounds. By confidence I mean both my ability to shoot the round, my ability to place the round where I want it, and also the ability of the round to stay in the thing I want it in. 9mm is perfectly adequate, but I would rather not risk the over-penetration for which the 9mm is known. Remember Jeff Cooper’s laws of gun safety, particularly “Be aware of your target and what’s behind it”, .40S&W and .45ACP give me the confidence to know that I will only kill my target when I pull the trigger. Other than that, it was an informative article.
Well what if all you CAN carry is JHP due to legislation? Wouldn’t then .45ACP be better than 9mm?
Sorry, meant FMJ
Often the legislative prohibits expanding ammunition, not specifically requiring FMJ. In that case I would pick something like the Underwood Xtreme Defender (not the Xtreme penetrator) in 9mm because it produces wounds larger that a FMJ and doesn’t carry the same risk of over-penetration. If the law specifically requires FMJ then I would probably still take a 9mm because I shoot it better. But I completely understand carrying a .45 too.
Abe, I have LEO cousin of over 26 yrs of duty, his description of what he has seen in “how” an assailant “reacts” to being hit (by different calibers), is as follows.
9mm = like assailant is being harrassed by an adamant “horsefly biting him”. Allowing assailant to continue on with their attack/advancement.
.40 S&W (and .45 ACP) = like assailant is being stung by a nest of irritated “assholes with wings” (AKA: Hornets & Wasps), thus rendering assailant as giving up MUCH QUICKER (sooner) than with 9mm.
He was on an undercover local drug enforcement in his early years (before taking position he’s held for the 26+ years), and had been in many shootouts due to this (come on now, IN Flint, Mi., Lol! One of the highest per capita murder rates yearly). He is concerned about self defense with his EDC he chose, being forced to use 9mm for his ammo, and severely wished that his EDC was available in .40S&W.
When he goes to restaurants anywhere near the locales he has policed over his career, he searches for the “corner without a cavity” so that he can watch his own front “six” for possible former offenders he’s arrested who may recognize him and want revenge and not allow them a shot from behind.
His Sig P229(?) he loves, but he absolutely hates the 9mm limit in cal selection. When I mentioned extra capacity with 9 vs .40, his reply was “IDGAS, I’ll take the slightly lower capacity of a .40, as I know it will do the job in less shots”. << his exact words.
Just sayin'. To each their own, but I'll take his word on how the two larger calibers are more effective per "hit".
His opinion contradicts a lot of data from the FBI (see my response to several previous comments), but I’m glad he has something he’s comfortable with. Like I said, pick the one you like the best. 9mm suits me, but it doesn’t suit everyone.
“Therefore, If a bullet can knock the bad guy down, it would also knock the shooter down.”
No no no no no no no . . .
You’re forgetting three things:
1. A bullet’s energy is developed as expanding gas pushes it down the barrel, so the energy that *is* transferred through the gun to the shooter, is quite different from the energy transfer of the bullet’s mass as it hits the target.
2. When you shoot (I hope) you brace the force of recoil with your entire body. Your arms act as complex fulcrums to absorb energy while maintaining control. Also, about 15-20 pounds of mass (the arms) isolate that force from your body. Again, this is quite different from a bullet unexpectedly hitting a body.
3. When a hollowpoint bullet hits a body, it expands and transfers the energy of its mass into a much larger area than the bullet’s original diameter which again, is completely different from the energy transfer the shooter experiences.
If you watch top shooters (like Jerry Miculek) they don’t flex their arms at all while shooting. They keep them rock solid. The wrists might move slightly, but not much. Additionally, look at a 9mm or 45 ballistic gel video. The gel blocks wiggle a lot but they are hardly blown away even though those gel blocks don’t weigh much. (less than twenty pounds if memory serves)
There is no way the “energy” itself from a pistol bullet will have any impact on an adversary as far as “knocking the person down.” Pistol bullets don’t have even remotely enough energy to do that. Anyone who believes this is carrying their pistol with a real false sense of security. There is only less than a mere scant 100 ft/lbs of energy between a 9mm and a .40s&w round anyway. There have been people hit numerous times with a 5.56 NATO round with its 1000 ft/lbs of energy and were not incapacitated. Even a rifle bullet will not “knock” someone down. The only way to stop an adversary is to hit him in an area of the body which incapacitates him. You only need enough bullet speed to penetrate these areas to sufficiently accomplish that task. Asides from the size of the bullet, the three common pistol rounds are basically even.
dumb argument .
If energy of bullet didn’t matter than a 50 bmg would be as lethal as a 45.
He emphasize “shot placement over caliber” here BUT forgot to mention that the cop in the story with the Glock 21 had also right shot placement. He hit the heart left and right lung, liver and one kidney and he still shot back at him. So that not only debunk .45 hp as stopping wonder but also shot placement!
Dude. What if the same guy was shot with a 9mm ?
I have read reports where a jacket (NOT INTENDED AS BODY ARMOR) caused 9mm to expand, and hit someone with the force of baseballs. No surgery. 12 rounds if I recall; this is a 25 year old report I read.
Dear ABE:
1. A very good friend of mine just sent me this email with your information in it.
All I have for you is several questions per the following;
1. I bought a .454 Freedom Arms Casull in 1987. I’ve had the privilege of seeing
someone shoot the right lower rear leg off a running white tail deer completely
off with this revolver.
2. This same pistol has dropped an African Lion, Cape Buffalo, and African bull
elephant with one round at 200 yards.
Do you know any human being that would not be stopped with such fire power?
If so, I’d like very definite proof from you to so describe so to me.
Looking very much for you reply.
To quote from the article: “But unless you have a rifle or very powerful handgun, don’t even worry about a damaging temporary cavity.”
The .454 Casull is a beast of a round and among the most powerful handgun cartridges available. It’s more powerful than quite a few rifle cartridges. So if by “stop” you mean “kill”, then it can stop very well. It would probably inflict so much damage the person would drop like a ton of bricks. However, if by “stop” you mean “Literally knock down”, then I have to disagree. Falling because they’ve lost consciousness or died is not the same thing as being knocked down. Physics is physics. If it would knock the target down, it would likely also knock the shooter down. For every reaction there is an equal and opposing reaction; no exceptions.
Also, please consider the context. I was talking about comparing three specific rounds only. I did mention more powerful handgun cartridges can do more, but they weren’t the topic of discussion.
I wouldn’t call seeing a deers lower hind leg off a “privilege”. If the deer was stationary, I’d say buy something that doesn’t make you flinch a foot, and if it was running, then that’s just plain irresponsible and unsportsmanlike. Hope a well placed follow up shot put the poor batard down and out of its suffering.
If you don’t think 45acp hits harder,watch hickock 45 shooting his metal tree arms with a 9mm then a 45.He even comments that the 45 makes them swing a lot faster.
i never said it doesn’t “hit harder”, I just said it can’t knock someone down. I’m just saying the these cartridges can’t physically knock someone down. For an experiment (though or actual) hang a 50-150lb sand bag and shoot that. You’ll see it moves very little. It’s a physics problem: if the gun could knock the target down, then it could knock the shooter down too. It’s Newton’s third law.
Abe, great article that gets you thinking. Your data shows not much difference between calibers as far as “stopping or killing power” but caliber choice should not be decided in a vacuum. You have to consider surroundings and where your target might be. For example, behind a door, behind glass or car door, wall or plywood etc. These scenarios are very specific but should be considered. Most police and military sidearms are decided by cost and contracts not what is “best” for their situation. Calibers are purpose driven that’s why there are so many.
Also the equal and opposite reaction does not hold true here. Because there are forces counteracting recoil (springs, buffers). So even if a bullets knocked over the assailant (which we know it couldn’t) it still would not affect the shooter in the same way.
.40 Caliber Smith & Wesson. It’s like if a 9mm Parabellum & a .45 ACP Sexed each other & has a baby. The .40 Cal S&W would be their B-A-B-Y.
It’s who we are as people & our strengths that allows us to shoot a specific caliber. Like a scrony person trying to shoot a .45 Vs a Strong person trying to shoot a .45. The conclusion is what we make it. It’s who is carrying the firearm and the firearms potential when discharged & if the perso who discharged the firearm had the ability to control that firearm correctly & was able to discharge the firearm correctly as the accurately strike the target. The conclusion is who We are as people & if We are capable of honing such a caliber…
A bigger fist hurts more when you are hit by a small fist, assuming the velocity is equal. Bigger is always better. Only weak shooters avoid learning how to control the bigger bullets. Man up and lift weights, squeeze a rubber ball with you hands and put in the time and effort at the range with the .40S&W, the .45ACP and even the .44 Magnum.
Your article uses “An Alternate Look at Handgun Stopping Power” by Greg Ellifritz as a reference for your statistics. Mr. Ellifritz does not list a single data point in his article and does not give any references to where the data he used can be obtained. His article is completely unsubstantiated and pretty much bogus. This in turn makes your article bogus. Tables of accumilated data without the underlying data available will not fly in ANY scientific circle.
Sorry!
I grow weary of people knocking the 40 S&W. They consistently use the 180 gr version as ammo for these so called evaluations. Don’t need a 180 grain in 357 in fact most people who know better would not carry even a 158 grain 357 in a medium barrel .357 (4″). No, people who are serious about surviving find the 125 grain optimal. In the same fashion a 155 grain high performance cartridge in a .40 is optimal. A 180 grain is just too slow. Even a 135 grain high performance round like and Underwood or Double Tap out of a 4″ barrel exceeds the power of a 4″ launched 357 Magnum and the 155 is damn close out of a 5″ 40 with either Bonded gold dots or XTP projectiles. Only and idiot would carry 180 grain ammo in a 40 for SD.
Hunting is different but the subject here is not hunting. I use 6 ” GP100 with Buffalo Bore 158 Bonded Gold dots up to 200 grain hard cast for hunting with great success, so much that I don’t even hunt any more as it has become so much less of a challenge In most of the US except of course for the big grizzlies in North and South Dakota and I keep a good distance when possible from them as I can’t bear (BEAR) to shoot those beautiful animals. I do carry a 375 H&H magnum rifle when in that neck of the woods as I am sure if my life depended on it, that rifle will stop most anything. Never had an occasion to use it against a large bear and would hate myself for destroying such a magnificent creature but would do it to save may life. I just know bears well enough to know not to do stupid things around them.
Forget that debate. I’d choose .410 and 000 buck or .36 cal. swaged lead balls in handguns or 10GA with 0 buck, #8 birdshot and 99% PAVA all under a patched and wax-covered 5/8″ steel ball in cut shells with a few grains extra powder each in a long gun. If it’s something more normal, what about a Glock 27 with Glock 22 mag, ported, lubed slide, lightened trigger and Lehigh .40 S&W Maximum Expansion ammo? Bigger holes and more of them at a reasonably fast ROF mean more blood loss and faster-collapsing lungs, plus more pain. I’d kidney stones twice. Biggest was the size of a grain of sand but it was debilitating. I can’t imagine how a 1.13″ object going through a channel in the body that’s freshly ripped would feel!
I meant 12GA. My mind was somewhat still on black powder shotguns.
A 45acp hole is not slightly larger than a 9mm it is over 60 percent bigger. The size of a hole is not measured only using diameter.
“I’m not recommending you carry a 22LR”
you just defeated your own argument.
“Studies of “stopping power” are irrelevant because no one has ever been able to define how much power, force, or kinetic energy, in and of itself, is required to effectively stop a violent and determined adversary”
and since it can’t be “defined” it is irrelevant ?
did someone claim this is a scientific study ?
then i guess … since “taste” cannot be defined .. a sh*t sandwich tastes as good as a peanut butter and jelly sandwich.
” Kinetic Energy does not matter. ”
and yet every african country that allows hunting big / dangerous game has a minimum energy
requirement … because historical experience proves that energy does matter.
“But it’s not with some mythical force called “stopping power” or “knock down power”. Consider this: Can you measure “Stopping Power” or “Knock Down Power”?”
yep … that’s why feather weight boxers win when fighting heavy weight boxers every time.
because weight and power have no correlation … and besides it does not matter … because it is only a myth.
yep … a .45 does not knock anything down any more than a 9mm … except for steel targets that don’t fall when his by 9mm … but do when hit by .45.
mass does matter.
I’ve SEEN a 44 mag round take a man off his feet. This was a terrible example to use. When we gathered the round from the vest, it was a SCHP. Expanded well, and deposited all the energy into our guy. Point is, there is knock down behind some of these bullets, it’s simple physics if the round is not a FMJ but does two things: expands enough grabbing tissue to transfer energy, and penetrates deep enough to hit thoracic cavity vitals. We’ve had members hit by 9mm in the vest that hurt, but the 44mag round, mentioned above, broke 3 ribs. Now, I’m not going to carry a 44mag or other big bore revolver, a 9 or 45 is always my go to. But the type of bullet is always heavily specific. Usually Critical Duty, X-Tac, Gold Dot HP, or Colt Copper HP. There’s options to say the least. Use what you hit with.