10mm Versus .45 ACP
BY Herschel Smith
6 months, 2 weeks ago
Richard Mann writing at F&S.
The situation where the 10mm Auto has the bigges advantage is for backcountry survival or bear defense. Loaded with something like Buffalo Bore’s 220-grain hardcast Outdoorsman load at 1200 fps, it will hit harder than any 45 ACP load, and because of the smaller diameter non-deforming bullet, will penetrate deeper, even deeper than a 180-grain Barnes Triple Shock bullet fired out of a 30-06 rifle!
That’s his conclusion paragraph. It’s true enough as it reads, but it’s incomplete.
He doesn’t consider use of 450 SMC, which would give him 230 grains running downrange at 1120 FPS.
Comparatively speaking, the hottest factory 185-grain .45 ACP load you can buy will generate only about 1,140 fps, and the fastest 230-grain offering only about 1,000 fps. Essentially, what you get with the .450 SMC are 10 mm velocities with a .45-caliber instead of a .40-caliber bullet.
I have no problem at all using a heavier bullet at comparable velocities.
Richard should expand his article (or do another one) on the use of 450 SMC and 460 Rowland. Actually, he should have written this one to consider all of the 45 options.
On October 16, 2023 at 10:34 pm, Dan said:
The biggest issue is probably availability. 10mm pistols and ammo are fairly easy to come by. 450 Rowland and 450 SMC require specially ordering parts or the gun and the ammo is extremely rare in stores and tough to find even online at times. Plus 10mm tends to be cheaper.
On October 16, 2023 at 10:44 pm, Herschel Smith said:
@Dan,
That’s a fair point, although I don’t shoot enough 450 SMC to cause a problem with availability. I shot it enough to know that I can handle it much like 45 ACP and that’s good enough. In fact, I returned to sight picture about as rapidly as with 45 ACP.
Other than that, what else do you need? Buy 50 rounds when it’s available for big game defense, carry it when in the bush, and then practice with 45 ACP the rest of the time.
On October 17, 2023 at 12:44 am, Georgiaboy61 said:
The whole 45 ACP versus 10mm debate is not an apples-to-apples comparison in the first place. The 10mm is a modern cartridge design which runs at ~ 37, 500 psi maximum pressure, whereas the 45 ACP is more than a century old, and runs at a much lower and more-modest value for maximum pressure, around 18000 psi give-or-take, or roughly half of the 10mm.
If you want to evaluate the real performance potential of the 45-caliber cartridge in its 45 ACP/45 Auto form, then you ought to look at one of the modern variants/wildcats, such as 45 Super, 45 SMC or 460 Rowland. These update the design into the 21st century by strengthening the case to be able to handle pressures at or even exceeding those attained by the 10mm Auto.
Since many handguns designed to use 45 ACP/Auto cannot handle pressures approaching 40K psi, they must be strengthened and updated also, to include higher-strength steel and also fully-support and enclosure for the cartridge case ~ as some older M1911s do not offer this feature.
The criticism that ammunition availability should disqualify these new .45-caliber marvels is disingenuous at best. Why? Because although there is plenty of 10mm Auto ammunition to be had in FA retail establishments, most of it is FMJ or JHP, designed either for target or anti-personnel/LE use and not hunting or protection from dangerous game.
Since this means that you may have to special order the proper 10mm ammunition for hunting and protection from dangerous game, much of the convenience vis-a-vis 10mm versus the new 45 variants is now moot, since 45 Super, 45 SMC and 460 Rowland can all be ordered in the same manner from Buffalo Bore, Underwood, the Hunting Shack, et al.
The hottest, heaviest loads for hunting large/dangerous game ~ whether in 10mm Auto or in one of the .45-caliber chamberings ~ are expensive to shoot, have substantially-greater recoil than most factory loads, and accelerate wear on your handgun. For this reason, it might make sense to limit how often you train with such loads, especially if your gun is not set up for it (i.e., does not have a stiffer recoil spring, etc.). Limit such full-house loads to just before you take that big hunting or hiking trip, and the rest of the time, give your handgun and yourself a break, not to mention your wallet.
The people at 460 Rowland can set up your FN FNX or other high-quality handgun in .45-caliber, to use their high-performance cartridge, but while retaining the ability to utilize standard-pressure .45 ACP loads. All that is needed is to swap out the recoil spring; you’ll use the stiffer rated spring for 460 Rowland and other hot loads, and the stock/OEM spring which came with the handgun from the factory, when shooting everyday 45 ACP loads. Magazines are likewise segregated into higher rate springs (which are faster and can handle the increased slide velocity) and stock/OEM “normal” rate springs for typical 45 ammo.
It is an elegant system, and there’s more: 460 Rowland brass is dimensionally identical to stock/normal 45 ACP brass externally, with the exception of being slightly longer than regular 45 ACP brass, which is a safety feature to prevent chambering in a non-460 handgun. To stay within the OAL (overall length) requirements for the 45 ACP, the bullets are simply seated a bit deeper than normal. Overall, their external dimensions are almost identical to those of the standard 45 ACP/45 Auto cartridge.
Internally, 460 Rowland brass is substantially thicker and stronger, especially in the case head area, to withstand the higher pressures of the cartridge. Starline, Inc. makes the cases, which are to a high standard and marked as “460 Rowland” to distinguish them from ordinary 45 ACP cases.
Standard .45-caliber (.451-.452) bullets can be used, although with the 460 cartridge and its much higher performance, a premium bullet may be needed to tolerate the higher MV and chamber pressures.
The result is a .45-caliber handgun which is dimensionally similar or even almost identical to a M1911 or other full-sized semi-auto handgun, but whose performance is on par with some 44 Magnum loads. The 460 Rowland people imprint their names on their conversions so that there is no doubt about what it is, and the conversions also use a muzzle device which is very distinctive.
Contrary to some claims, the performance of the stoutest 460 Rowland loads does not surpass the hottest, hardest-hitting 44 Magnum loads, but the 460 does overlap considerably at the lower-to-middle levels of power, which is no easy feat to do in a semi-automatic handgun. On a per-shot basis, 900-1200 ft-lbs. of kinetic energy at the muzzle is nothing with which to trifle… but that’s what the 460 conversion can deliver.
And it is worlds more-comfortable and pleasant to shoot than the typical 44 Magnum revolver. Why? Because the operating system of the handgun takes up so much of the recoil which in a revolver goes straight back into your hand, wrist and arm. The muzzle device helps a great deal, as do the other refinements done in the conversion.
And the 460 conversion is capable of fine accuracy, too, which rounds out a very capable system.
While a 460 conversion semi-auto handgun can’t match the hardest-hitting 44 Magnum loads, it totally beats the wheel guns in capacity, with as many as fifteen shots on tap (depending on the model of handgun), and even in a M1911 converted to 460, you still have 9-10 shots with an extended mag rather than the five or six of a large-frame revolver.
On October 17, 2023 at 1:00 am, Georgiaboy61 said:
Now, let’s look at the 10mm Auto side of the debate….
In spite of being intrigued by the various offerings in high-performance 45-caliber cartridges based on the venerable 45 ACP/45 Auto cartridge, and being a total fan-boy of the M1911, I like the 10mm Auto a great deal. I even like its little brother, the 40 S&W, too, which is also a very fine and capable chambering.
Look, I get it totally… some people don’t want to go to the trouble to get a 45 Super, 45 SMC or 460 Rowland conversion done, or they don’t have the resources for it. For them, the existence of so many high-quality pistols in 10mm Auto is a blessing. If even that is too much work to sort through, i.e., which manufacturer and model to buy, it gets even easier…. especially if you like Glocks.
The reports are that Glock 10mm Auto pistols are now all the rage among professional hunters, guides and other outdoorsmen up in Alaska and the Yukon. In particular, Glock 40 “Long Slide” models are very sought-after. They sport 6-inch barrels and hold 15 rounds in their magazines, plus one in the pipe. The additional inch or two of barrel is for squeezing out as much muzzle velocity and kinetic energy from the rounds being fired. Stuff your new Glock 40 full of a suitable bear defense or hunting load and you’re good to go.
Although the 10mm Auto gives up some power in comparison to a 460 Rowland, it far outstrips a standard M1911A1 in terms of performance, and many hardcast or other premium hunting/large game loads offer tremendous performance in terms of penetration, wounding capability and so forth.
For those keeping track, 10mm Auto performance often overlaps with that of many time-tested and trusted 357 Magnum loads used by Elmer Keith and other handgun hunters in the old days.
To bring things full-circle, modern advancements in cartridge and bullet design, as well as state-of-the-art propellants ~ are allowing manufacturers such as Buffalo Bore and Underwood to offer 357 loads which rival lower-end 44 Magnum performance, or even a 460 Rowland! 850 ft-lbs. of mechanical energy is no small thing, but that’s what the hottest, hardest 357 loads are now doing.
On October 17, 2023 at 7:30 am, Frank Trappist said:
I’ve got a Rowland conversion on an XDm, and a much better brake than the one sold by Rowland. It can blow out the overhead light bulbs in an indoor range.
I chicken out by the time I get to mid-range .44 Mag power. Case head expansion, flat primers, and so forth. But it will easily shoot 275 gr. bullets at 1050, or huge meplat 215s or 230s at 1200. That’s classic .45 Long Colt power, if not .44 Mag.
I don’t like being handicapped by the comp though. Finding a good holster for the gun so equipped is difficult, making it less useful for hog or bear defense. I’m thinking sticking with the .45 Super level, 275 gr. at 900 fps, would be the best compromise. But I’m not actually likely to encounter bears.
Those 275 Hunters Supply bullets work really well at ACP pressures too… huge meplat, and very accurate. Not a lot of interest in them but they would be my choice in ACP for any kind of animal defense. They will be unsexily slow… like 700 fps though.
On October 17, 2023 at 4:15 pm, Georgiaboy61 said:
@ Frank Trappist
Re: “Those 275 Hunters Supply bullets work really well at ACP pressures too… huge meplat, and very accurate. Not a lot of interest in them but they would be my choice in ACP for any kind of animal defense. They will be unsexily slow… like 700 fps though.”
That’s not necessarily a bad approach. Big, dumb and slow slugs have been laying ’em down for years, whether from handguns or long guns. My understanding is that in the Old West, 45 Colt handguns and carbines were considered effective against a variety of large game species ~ including the big bears ~ when firing 250-grain lead slugs at sub-1000 fps MV.
What those big heavy slugs lack in kinetic energy due to high velocity, they make up for with depositing their energy inside the target rather than on the other side of it due to a through-and-through, and impressive momentum. Both of which matter a lot when it comes to taking game.
That’s my take on it, anyway. I puzzled over it for a good while, though. Conventional wisdom says that rifles with relatively low muzzle velocity (compared to modern alternatives) ~ such as the 30-30 WCF and .303 Enfield ~ are insufficiently potent to take large/dangerous game. Yet, here in the ‘States, the 30-30 has been getting it done for more than a century, and up in Canada and around the former British Empire, the same holds for the venerable .303. What gives? What is going on?
These rifles, loaded with round-nose or flat-pointed bullets in their respective cartridges, may not have stellar MV numbers by modern calculations, but they do have the ability to fire a tough and durable slug of around 170-180-grains which will penetrate deep and deposit most if not all of its energy inside the target instead of having so much power that it passes completely through the game animal and does not do that.
Their slugs may not be all that aerodynamic, but they make up for it by being bulldozers that don’t let much get in their way. Modern terminal ballistic studies have seemed to confirm this last point: Spitzer or pointed projectiles may deflect off of or push-aside obstacles encountered in the terminal phase of flight rather than causing them to shatter, break or otherwise be damaged in a more-extensive fashion.
The foregoing, if correct, would explain why some traditional bullet designs/profiles seem to perform so well on large/dangerous game, and why certain cartridges punch above their weight in field performance.
The same effect applies to the 45 ACP: The Hague and Gevena Conventions prohibit the use of expanding/hollow-point or “dum-dum” ammunition, thereby limiting signatories to full-metal jacket (FMJ) or “ball” ammo. John Browning could not, therefore, employ the former to enhance the performance of the round his M1911 pistol would use.
Instead, he devised a heavy, blunt 230-grain slug which, by moving at relatively modest velocity (~ 830-860 fps) would deposit the bulk of its energy inside the target and also produce a wider wound channel than smaller caliber slugs. The result was an extremely effective pistol and cartridge which served for more than a hundred years with great distinction in both military and LE applications, and which is still in widespread use today.
It would seem that a good idea is a good idea, no matter how old it is….
On October 17, 2023 at 5:09 pm, MTHead said:
“Even deeper than a 180-grain Barnes Triple Shock bullet fired out of a 30-06 rifle!”
I’m calling BS.
A 180 grain slug out of a ’06 is traveling at 2700 FPS. I’ve put them through 3/8″ mild steel at 200 yards. Think your 10mm can do that? Not hardly.
Yes, hollow points do tend to slow down in meat faster than solids. But ain’t no way in hell a 10mm outperforms a 30’06 with 180 grainers. Especially ones that are made to penetrate large game like the Barnes are.
Even with the dynamic of speed/surface tension in play.
There are really good reasons bear guides carry 416’s. Go ask them if they would rather have an ’06 or a 10mm in bear country?
I don’t need to ask Mr. Mann for the answer.
On October 17, 2023 at 11:06 pm, Georgiaboy61 said:
@ MTHead
Re: ““Even deeper than a 180-grain Barnes Triple Shock bullet fired out of a 30-06 rifle!”
I’m calling BS.”
“A 180 grain slug out of a ’06 is traveling at 2700 FPS. I’ve put them through 3/8″ mild steel at 200 yards. Think your 10mm can do that? Not hardly.”
Your logic is very sound, so well-said and well-done…
On October 18, 2023 at 12:23 pm, =TW= said:
Expected circumstances should suggest hardware choices.
.45ACP 200-230gr RNFP or SWC at 950 FPS in a reliable platform should be pretty effective.
10MM in a short, handy carbine maybe even more so.
Best to bring enough gun.
On October 18, 2023 at 2:12 pm, Herschel Smith said:
I believe CMMG makes PCC in 10mm.
On October 18, 2023 at 6:55 pm, MTHead said:
Thanks Georgia. It amazes me what people will say for money. Although he might have some obscure gel test to back him. Live charging animals that think your lunch? That would be something to watch! (From a good distance of course.)
On October 19, 2023 at 10:19 am, Latigo Morgan said:
If you have a dangerous animal encounter, it is going to be up close, within 10 yards or less. Better be able to dump as much destruction into it as you can, as fast as you can, to make it stop.