Ayoob: Is the .45 Obsolete?

By Massad Ayoob
Posted in #Gear
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Ayoob: Is the .45 Obsolete?

May 13th, 2021

6 minute read

I keep hearing that the .45 ACP is obsolete. “It doesn’t hold enough ammo!” “All service calibers are equal!” “It kicks too hard!” “Its ammo is too expensive!” “It’s too big and heavy!”

Having been a .45 ACP shooter for 60 years now, this writer begs to differ.

Federal Hydra-Shok Deep cartridge in .45 ACP
The Federal Hydra-Shok Deep is a good example of modern defensive cartridge design. It is shown here in .45 ACP. Image: Federal


Yes, a 9mm (and for that matter, a .40) holds more rounds in the same space than a .45. However, I remember a long-ago conversation with a brother lawman from an adjacent department. My department’s issue gun was a nine-shot .45 ACP, while his agency issued an 18-shot 9mm.

Springfield XD-M Elite pistol in 9mm with ammo
A double-column pistol like this XD-M Elite Precision 5.25” gives you impressive capacity in 9mm.

When he boasted about a service pistol that had twice the on-board cartridge capacity of ours, I replied, “That’s one way to look at it. Of course, you guys have 115-gr. 9mm duty ammo, and our .45 pistols take a 230-gr. load. Your officer and mine each have the exact same amount of lead in hand to inject when they draw their guns, but mine injects a double dose every time they pull the trigger.”

My tongue was partly in cheek when I said that, but consider the following two points:

Not everyone can take advantage of “high capacity.” Many states limit law-abiding armed citizens to ten-round magazines. If the Biden Administration lives up to its campaign promises, that ten-round limit may go national. For comparison, that’s nine rounds of .45 ACP defensive ammunition in your 1911 to 11 of 9mm in the same size gun.

High capacity .45 ACP pistol
Who says .45 ACP has to be “low cap”? This XD45 Tactical takes 13 in the mag and one more in the chamber.

It ain’t like we don’t have double-stack .45s. My Springfield Armory XD-M 9mm pistols hold 19+1 rounds (and the new full-size Elites pack in 22+1). My XD .45 pistols, essentially the same-size package (and yes, I’ve carried both concealed), take 13+1 rounds of .45 ACP. And I certainly don’t feel under-gunned when I’m carrying a 9+1 1911 .45.  Your needs and comfort level, of course, may vary.

.45 ACP and a 9mm pistols shown side by side with ammo
The .45 ACP vs. 9mm is a long-standing debate. Springfields shown are Range Officer .45 (left), and Ronin 9mm (right).

Relative Stopping Power

The theory that “9mm equals .45” is always accompanied by the explanation, “advances in bullet technology have improved the 9mm’s terminal ballistics.” The latter part is true, but the jury is still out on the first part. Widely accepted theory is not necessarily conclusive fact especially on the subject of the best defensive caliber.

Speaking of fact, wound volume is still a “thing.” Assuming identical shot placement and wound track angles, the larger wound should have the greater incapacitating effect. Gunfighting expert Jeff Cooper had a different background than military combat surgeon and wound ballistics authority Martin Fackler, MD, FACS, but each came to the same conclusion on one thing: assuming the same bullet configuration, a .45 slug could cut a 60% larger wound channel than a 9mm.

Ayoob shooting a bowling pin match
At the Pin Shoot in Michigan, 230-gr. HST +P from the author’s Springfield TGO-II sends heavy bowling pin flying. Image: Gail Pepin.

Charles Schwartz, author of the book “Quantitative Ammunition Selection”, used three different scientific models to compare 124-gr. 9mm to 230-gr. .45 ACP, each with full metal jacket ammunition. The Q-Model resulted in 33.584 gram total wound mass for 9mm, and 48.854 gram wound mass for .45. The mThor Model came out to 34.022 gram total wound mass and .45 ACP, 50.354 gram wound mass. The MacPherson Model was 36.096 grams total wound mass for 9mm, and 57.704 with the .45.

Lead to Spread

The fact is that a .45 bullet has “more lead to spread.” True enough, today’s best 9mm is expanding as well as yesteryear’s .45 ACP jacketed hollow points (JHP), and perhaps more consistently.

Expanded vs. unexpanded Federal HST bullet
You won’t find 9mm rounds that expand as wide as this Federal HST 230-gr. +P .45 ACP.

However, I’ve never seen a 9mm bullet expand to a full 1″ in diameter in living tissue. I’ve seen that with two .45 ACP loads: the old Speer 200-gr. driven at +P velocity from a 4.25” barrel, and the current Federal HST 230-gr. +P at 950 feet per second from a 5” barrel.

And if the bullet doesn’t expand … Heavy clothing and other barriers have been known to clog the hollow cavities of even high-tech JHP bullets, bringing us back to full metal jacket “hardball” performance. See the comments of Cooper, Fackler and Schwartz, above. If you’re in a frigid clime and your opponent is likely to be heavily clad, when your JHP turns into FMJ you probably want it to be a big FMJ, and that favors .45 ACP.

Federal Premium Personal Defense .45 Auto box of ammo
Advanced designs like the HST have benefitted the 9mm cartridge greatly, but that’s true in .45 ACP, too. Image: Federal

The ammo drought of 2020, still in effect, hit the 9mm supply the hardest due to 9mm’s current popularity. I have been in gun shops where they had only FMJ for sale in either caliber, and little of that. The anecdotal history from WWI (and on) of the 9mm vs .45 debate generally favored the .45 over the “nine.” Just sayin’ …

Cost Factor

Of course, .45 is more expensive. Lead, brass and copper cost money, and the larger cartridge uses more of each. “Duh.”

Interestingly, though, due to that greater demand for 9mm, I’ve recently been in gun shops where they had limited amounts of each caliber, and the .45 was actually cheaper due to the greater demand for the former. Don’t expect that to be the case when and if ammo supply returns to normal, though.

Shootability Factor

This “depends.” In similarly sized pistols, the .45 “kicks” more. However, I’ve found that this is highly individual. With dedicated shooters, the difference in the speed/accuracy balance between 9mm and .45 ACP isn’t as much as people think.

Massad Ayoob with Springfield .45 pistol and ragged target grouping
A .45 can be very shootable. The author’s Range Officer has put 60 230-gr. slugs through this ragged group in demo shoot for students in Alaska.

The more the shooter knows how to control a pistol at speed, the more that difference is diminished. You really have to get to the range with a timer, score the targets, and see how your own hit factor and speed factor balance with one another, with each caliber.


Each of us needs to balance our own needs. Competence engenders confidence, and vice versa. If you shoot significantly better at speed under stress with a 9mm, by all means, carry one. If you’re arthritic, as I am, 9mm will be more comfortable to shoot. Hell, I’m a .45 fan and carry 9mm more than .45 lately.

High capacity pistol for concealed carry
A polymer-framed, double-column mag gun might be a great fit for your carry needs.

Current events do indeed engender a bit more confidence in a higher-capacity gun, where that is legal to carry. When I have to fly to a firearms training venue, the general 11-lb. limit of ammo in checked baggage allows me to carry twice as much 115-gr. 9mm as 230-gr. .45 ACP, but I make sure to have the best possible 9mm carry loads with me for when I’m on my own time instead of on the range. Bullet design does seem to be more critical to optimum performance in smaller calibers.

We each need to make our own choices. Following the herd is sometimes the best choice … but sometimes not. Only you should determine what’s best for you.

And when you consider everything and weigh that balance, you may well find that the .45 ACP is nowhere near as obsolete as some say it is.

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Massad Ayoob

Massad Ayoob

Massad Ayoob is a renowned firearms expert with decades of experience in the firearms community. He's the author of more than a dozen books and hundreds of articles and has extensive experience as a law enforcement officer, competitive shooter and expert witness.

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