9 mm vs. .45 ACP – A Different Kind of Comparison
BY Herschel Smith
2 years, 1 month ago
It’s true that the best 9 mm loads are equal in performance to many .45 ACP loads. However, if recovered-bullet diameter and penetration mean what we think they do, the best 9 mm loads are not the equal of the best .45 ACP loads. Regarding capacity, a first-grader can see a 9 mm pistol holds more ammo, but most civilian self-defense shootings are resolved with between one and eight shots. So, capacity might not be all that important after all. But what about shootability? Are 9 mm pistols that much easier to shoot more accurately and faster? To find that out, I conducted a test to get to the bottom of the 9mm vs .45 ACP debate.
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The 6.32-cubic-inch crush cavity delivered by the Federal 230-grain +P HST load is impressive, but it comes with a cost, and that cost is an uncomfortable shooting experience and an increase in the time it takes to fire multiple shots. Measuring recoil can be subjective, but more never helps you shoot better. Everyone will have different limits, but at some point, you must decide if the terminal performance you gain is worth the reduction in shootability that comes with it.
What the information from this test—and the massive spreadsheet created to digest it—might do best is to explain why most law enforcement agencies have gone back to the 9 mm. With the best 9 mm loads, you get terminal performance similar to standard .45 ACP loads out of a gun that holds more ammunition and is easier to shoot fast and accurately. But, what this also shows is that with a .45 ACP, you can select a lesser-recoiling load and shoot nearly as fast and accurately as you can with a 9 mm pistol, while delivering similar terminal performance. If you do that, the only thing you’re giving up with the .45 is capacity.
This is an odd article by Richard Mann. He spends most of his effort testing and discussing ordinary .45 ACP rounds, but frankly I’ve never seen PD .45 ACP rounds. They are all +P ammunition. Furthermore, jacketed ball rounds for dangerous game defense are certainly all +P, and some are +P+ (such as with Double Tap 450 SMC, Underwood and Buffalo Bore).
He admits as much in both the front and end of the article, and yet states that the only thing you give up by selecting the .45 ACP is capacity. So he admits that the .45 ACP +P has more effect than the 9mm, and then discusses giving something up to carry it (like capacity).
I think this article needed an editor.
But there’s one more thing missing in this analysis beyond “recoil,” however that is felt. The 9mm is a higher pressure round (35,000 psi chamber pressure) compared to the 45 ACP (customarily 25,000 psi, but admittedly higher with +P+ ammunition). There is simply a difference in feel, some call it a push versus snappiness. I would liken it to the difference between shooting the 30-30 and 5.56mm (the former being at42,000 psi, whereas the later is 62,000 psi).
For me the bottom line is purchase and practice with both. Use whatever you feel the best shooting in the circumstance. But I’d never liken the performance of the 9mm with 45 ACP +P+ for dangerous game.
For dangerous game, carry a big bore cartridge.
On September 22, 2022 at 10:36 pm, Fred said:
“With the best 9 mm loads, you get terminal performance similar to standard .45 ACP loads out of a gun that holds more ammunition and is easier to shoot fast and accurately.”
This has not been my experience, not even close. The 9 is very difficult to shoot, being snappy, thrusting the muzzle skyward, it takes more time to recover back to front sight alignment than with 45 acp.
First shot landed wins the gunfight. People hate being shot and any caliber landed is effective 99 percent of the time in getting an attacker to disengage. Having said that, I do carry a large bore handgun with lots of rounds.
“Regarding capacity, a first-grader can see a 9 mm pistol holds more ammo”
Well, maybe a first grader can, but once someone is very well educated in America they can’t. (Sorry couldn’t resist.)
On September 22, 2022 at 11:16 pm, BAP45 said:
Years ago I watched a ton of side by side gelatin footage of 9 and 45. It looked like 45 did perform better but the increased performance didn’t seem to be so substantial. So essentially getting double the capacity for the price of only a marginal loss of performance would be pretty compelling to most.
On September 23, 2022 at 1:01 am, Dan said:
For dangerous game carry a long gun.
As for 45 acp vs 9mm in self defense situations…..mag capacity is becoming a
much more important issue because criminals are starting to operate in bigger
groups. 6 to 8 rounds is probably adequate for one goblin. For several you can’t have
too many rounds in a magazine.
On September 23, 2022 at 1:33 am, Rick said:
I shoot my 1909 Colt (.45 Colt) more accurately than the H&K or Berretta, both in 9 mm.
The same goes for my Ruger Super Blackhawk in .44 Mag.
Maybe its the size of the frame. I think it is.
On September 23, 2022 at 1:37 am, Rick said:
To Dan’s point, each holster for my 9 mm feature spare mag pouches. I also have pockets. I am a firm believer that if one is to carry,cthey must be on their game as far as mag changes/reloads.
On September 23, 2022 at 6:24 am, xtphreak said:
Not all hollowpoints expand.
An unexpanded 45ACP is still .45 where an unexpanded 9mm is still .355.
Bigger bores poke bigger holes.
Bigger holes leak more blood.
Bigger holes let more air in.
Bigger holes have a larger chance of hitting vital organs, breaking bones.
On September 23, 2022 at 8:03 am, Latigo Morgan said:
I guess the best comparison of the two is in the meme I saved a long time ago. It shows the backs of two women side by side at a shooting range.
The lean, athletic gal is 9mm and the (nicely) curvaceous gal is .45.
I’d go home with either one of them and be quite happy.
I shoot the .45 better than the 9mm mainly because that’s all I shot for thousands of rounds because I was a .45 snob and wouldn’t touch a 9mm. Then I grew up and am now of the mind that if it goes “BOOM”, I like it – no matter what the caliber.
I prefer having several different tools in the toolbox than just one wrench.
On September 23, 2022 at 9:21 am, Double mountain man said:
Cost of practice ammo comes into play for me. I carry and practice w a 9.
Not to mention availability.
On September 23, 2022 at 9:28 am, Bradley A Graham said:
I will be the pariah, just get a .40 S&W…………….
On September 23, 2022 at 10:12 am, George 1 said:
@Bradley A Graham
If the author is debating over capacity vs stopping power (of the 9mm) then the .40cal should be his choice.
The .40 cal and the .45 ACP are actually very close in ft lbs of energy with comparable loadings. For instance:
Buffalo Bore .45 ACP 230 gr JHP +P: at the muzzle 950 FPS and 461 ft lbs of energy.
Buffalo Bore .40 Cal 180 gr JHP +P: at the muzzle 1100 FPS and 484 ft lbs of energy.
So for defense against criminals you can do very well with the .40. However you will never get the .40 up to .450 SMC or .45 Super energy.
On September 23, 2022 at 10:42 am, DAN said:
They are both pistols. The difference can only be minimal. Any bullet which would increase the effectiveness of the 9 would certainly do the same for the 45. The “shootability/feel/concealability” of a pistol to a shooter is of much more importance than the caliber.
And while most shooters think bullet expansion is how to judge a cartridge, I disagree. I carry FMJ. I think penetration is the most important issue (and reliability, which FMJ is known for. What good will a perfectly mushroomed bullet do, if it is slowed by a heavy coat and fails to penetrate deep enough to be effective? (has happened). Solid bullets are commonly used for big dangerous game for a reason.
Just my 2 cents.
On September 23, 2022 at 10:45 am, Scotty said:
I’ll just leave this here…
10 millimeter Auto
That is all.
On September 23, 2022 at 11:39 am, Heywood said:
Coke. Pepsi. If you know what I mean….
On September 23, 2022 at 12:23 pm, =TW= said:
Hardball vs. hardball: .45ACP over 9mm.
Expanding ammo: A toss-up.
Capacity: 9mm. Probably.
Platform: Pick your favorite.
Extra mags: May come in handy.
Practice: Yes.
On September 23, 2022 at 1:22 pm, Ron Bass said:
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On September 23, 2022 at 1:57 pm, Furminator said:
45 won two World Wars, 9mm lost two World Wars.
On September 23, 2022 at 9:27 pm, Georgiaboy61 said:
@ Furminator
Re: “45 won two World Wars, 9mm lost two World Wars.”
Apologies for not having all of the specifics, but I heard a tale once years ago about the predawn hours of June 6, 1944, when U.S. (and British) paratroops were landing all over Normandy. One young U.S. trooper – can’t recall if he was 82nd or 101st Airborne – landed near a hedgerow, and after hurriedly disconnecting his chute and hiding it, and getting his wits about him, went to investigate a sound on the other side of the hedgerow.
At virtually the same instant, the American paratrooper clutching his M1911 .45 ACP and a German soldier with an MP38-40 9mm Parabellum submachine gun on the other side of the obstacle, arose to see what lay beyond his own position.
The German fired first, scoring five hits with his 9mm Parabellum submachine gun; fractions of a second later, the American fired with his M1911 .45 ACP. The American scored only one hit with one of those big 230-grain FMJ slugs, but it was enough: The German died then and there, the American survived the night and the war to die many years later of old age.
Not for nothing was the saying in the old Depression-era days: “They all fall to hard-ball!” “Hardball” being street-wise slang for those big 230-grain FMJ slugs fired by the M1911.
John M. Browning’s key insight was that many smaller-caliber, faster-moving bullets over-penetrate and do not therefore deposit the bulk of their energy inside the target during the terminal phase of flight. Not only does the comparatively massive 230-grain slug put a larger diameter hole or channel in the target, because of its mass (more than twice the weight of many pistol slugs in smaller calibers) and large cross-section, it excels at breaking bones, damaging soft tissue, and also depositing its energy in the target, where it will do the most good.
The reason that paratrooper survived in Normandy is partly due to luck; the German’s shot placement wasn’t as good as that of the American was – but it was also due to the fact that 9mm FMJ is famous for over-penetrating and just leaving a caliber-sized hole in the target.
It is germane to note that trauma surgeons have stated numerous times in forensic studies and elsewhere that small-arms wounds caused by handguns in 9x19mm, .40 S&W and .45 Auto/ACP are indistinguishable in-situ if hollow-point or expanding ammunition was used. By which is meant that the damage done is similar-enough in appearance that identification of the caliber of the projectile or the weapon which fired it, is not readily-apparent on the basis of tissue damage alone. For that, recovery of the slug is needed, or other forms of evidence.
But, if one is shooting hardball – as Clint Smith recommends – then the bigger the bullet, the better.
Many defensive handgun trainers recommend switching out your ammo depending on the time of year, if you live in a place where people bundle up a lot in the winter. HP or expanding loads are fine against lightly-clothed assailants, but FMJ or other types of loads which penetrate better may be indicated when winter rolls around.
Definitely a judgment call, though, because over-penetration risk is one that must be managed; in the eyes of the legal system, you “own” every shot you take.
On September 23, 2022 at 9:57 pm, Bones said:
The rules of physics operate without considering the politics of law enforcement agencies or their administrators. Firing a bigger bullet at a significant velocity will always be a better man-stopper when compared to a smaller bullet at that same velocity. The greater energy delivered will always do better.
Of course, ammo designed to punch through a barrier, or armor, will use its energy to accomplish that, leaving excess energy to cause wound damage. In general, however, bigger defensive bullets driven at high velocities will always beat lighter bullets at those same velocities.
When the FBI determined that their agents scored better with the Glock 9 versus the Glock 40, they switched. If you shoot the 9 better than the 40, maybe you should shoot that. If you shoot the 45 better than the 9, shoot that. Of curse, if you suspect that you may have multiple assailants, the 9 may be the way to go.
I generally carry a .45, a Detonics Combatmaster. If I’m heading to the big city, I might carry the P320 in 9mm. 18 rounds in the gun, 21 as a spare mag. Somedays I carry the P365 in 9, if the concealment calls for it.
YMMV.
On September 24, 2022 at 1:23 am, Georgiaboy61 said:
@ Bones
Re: “When the FBI determined that their agents scored better with the Glock 9 versus the Glock 40, they switched. If you shoot the 9 better than the 40, maybe you should shoot that.”
The back-story on that switch from 40 S&W to 9mm that I heard was that the F.B.I. was looking for scapegoats after the Miami shootout in 1986 and decided to blame their sidearms rather than examine their training procedures more-closely… but that’s another story, right?
Thanks for writing…
On September 24, 2022 at 8:37 am, George 1 said:
The linked study is the latest data from medical examinations of gunshot wounds.
The bottom line?
Of the commonly carried self defense calibers the ONLY standout was the .45ACP. It wins over even the 357 magnum, (in this study). Also bullet type and design do not seem to matter much. What does matter is hits on target. We are all aware of that.
https://gundigest.com/article/a-medical-perspective-on-ammunition-and-lethality
On September 24, 2022 at 1:08 pm, MTHead said:
To me it comes down to what one wants to do a certain time. Every system is a series of compromises. The 9mmv45acp is no different.
You should keep in mind that the 45 has a slower recoil impulse. And in small firearms has a tendency to not fully cycle if somehow limp-wristed.
Which gives the 9 an edge in concealed carry. But anytime I can my XD45 gets the nod. Not much beats the comfort of having 15 rnds. of 45 close to hand. (+1 mag ext. with one in the pipe.)
There’s good reasons for most all gun/caliber choices. Why limit oneself? We should spend more time getting good with every firearm we can get our hands on.
After all it is a gift from God, through St. John Browning!
On September 24, 2022 at 1:30 pm, Georgiaboy61 said:
Re: “Of the commonly carried self defense calibers the ONLY standout was the .45ACP”
What’s the quip the one lawman made back in the old days when asked why he carried a Colt .45… his reply was “Because they don’t make a Colt 46!”
On September 24, 2022 at 3:25 pm, Bones said:
@Georgiaboy61
Yes, the Miami shootout was the impetus for the switch, briefly to the 10mm, and then to the .40 S&W. And yes, the fault was placed on “the gun,” while ignoring the fact that they weren’t prepared for the LE activity, no vests were worn despite the likelihood of a felony car-stop, and the fact that multiple agents had semi-auto pistols in 9mm, and some had revolvers in .357 mag. (Also that two agents were “getting some” from a broad at a hotel room, or so I read.)
The FBI also moved to place long guns in the cars, the magical MP-5 SMG, again in 9mm and eventually in 10mm. (Don’t get me wrong, I luv me some MP-5, but I luv me some M4/M-16/Car-15 more).
On September 25, 2022 at 1:15 am, Georgiaboy61 said:
@ Bones
Re: “The FBI also moved to place long guns in the cars, the magical MP-5 SMG, again in 9mm and eventually in 10mm. (Don’t get me wrong, I luv me some MP-5, but I luv me some M4/M-16/Car-15 more).”
According to the incident reports and after-actions I’ve seen in open (public) sources, Platt and Matix had a substantial advantage in that gunfight because of Platt’s Mini-14, the only rifle in the fight. So it makes sense that they would start equipping their people with similar.
This incident and also the North Hollywood shootout, really changed LE perceptions of how to arm themselves (Man, I am dating myself! Yeah, I’m that old….). To hear it told, back in the day, most cops had at most a 12-gauge pump-gun in the car, and rarely a center-fire rifle. Well, depending on agency, maybe an old M-1 Carbine.
The only reason I know any of this stuff is because for a period of years when I was younger, I trained almost every weekend with a club which did practical handgun shooting, IPSC stuff mostly, and few members were current or former cops and also a few who were prior service military.
On September 25, 2022 at 8:07 am, Pat H. Bowman said:
I read that article last week and it seemed a bit like the tests were designed to generate the results to prove the conclusion that was already drawn. That is, don’t carry a .45, the 9mm is better. While I do carry a 9mm almost all the time, I found their use of percentages without explanation troubling. As the saying goes, “Figures don’t lie, but liars sure can figure.”
Whenever I see something is 18% faster, I want to see raw numbers. In this case, the largest spit time difference was less than .1 sec. Does that make a difference? Maybe. When trying to win a match? Sure. In real life? I doubt it.
Having recently acquired a new Springfield TRP in .45, I was actually surprised how fast I could shoot it accurately. Perhaps it’s just because I shoot 1911s so well, but my split times are hardly slowed at all and the .45s land right next to each other instead of two inches away like they do shooting my 9mm polymer guns (that I have literally 15,000 rounds through).
Even acknowledging Mann’s assessment that they could “shoot 5-6 9mm rounds as fast as 4-5 .45,” if one puts 4-5 .45s into a 2″ cluster in the high thoracic cavity, I’ll venture to say the fight is over.
At the end of the day, both rounds are capable of stopping fights, and both have failed to do so, sometimes spectacularly. As Garand Thumb likes to say, “None of this matters without training.” Train, practice and get really, really good with your carry gun/round of choice.
And don’t get me started about the Miami-Dade shootout. The cops got their asses kicked not because the 9mm wasn’t up to the task, but because of their piss-poor tactics, their complete failure to take the threat seriously and they didn’t bring the proper tools/people for the job. In their arrogance of being **The FBI**, they thought two hardened killers would just fold up like wet napkins before their presence. They found out.
On September 26, 2022 at 5:44 am, Roger J said:
My FNX-45 carries 15+1 rounds. With all the capacity I need, why would I switch to a 9mm? I do love my Hi Powers, they are a blast to shoot and combat proven but they are not .45s.
On September 26, 2022 at 4:15 pm, =TW= said:
Since expanding self-defense bullets are known to fail on occasion, what solid bullet profiles might be more effective than roundnose hardball?
RNFP?
FP Conical?
SWC?
Solid copper “extreme”? (And why are there no lead bullets like these?)
Obviously, feeding, penetration (and overpenetration) and tissue disruption are factors to consider, speed and bullet weight will affect energy transfer.