10mm vs 45 ACP: Battle Of The Big Bore Bullets

Should I Get A 10mm or .45 ACP?

If you want an autoloading big-bore, the two most obvious choices are going to be down to 10mm vs. .45 ACP. There are others, of course. The .44 Automag is coming back, there are the Wildey magnums, you could also get a Desert Eagle and so on.

However, if you don't feel like blowing almost $2 per round, the 10mm and rounds are really the most realistic choice.

Which is better? Well, the question is "better for what?" Both rounds are proven performers, but also have certain best uses. The bigger, slower, heavier .45 ACP is a pure personal protection round. The 10mm is a true all 'rounder, but makes certain demands of the person carrying it.

Which is best for you is really the question. Which will be, though? Let's go over that a little more.

Is 10mm Bigger Than 45?

Is the 10mm bigger than the 45? Yes it is...and no it isn't.

Huh?

The quick version is the 10mm has a longer case, but the .45 ACP has a larger projectile. The 10mm also has a shorter bullet.

The longer version goes a little more like this:

	10mm Auto	.45 ACP
Bullet diameter	0.4 in	0.451 in
Case diameter (neck)	0.425 in	0.473 in
Case length	0.992 in	0.898 in
Overall length	1.26 in	1.275 in
Chamber pressure	33,000 psi	19,000 psi

So, as you can see, the 10mm isn't as big around, but generates more than 1.5 times the chamber pressure of the .45 ACP. This means bullets go faster! However, said bullets also go faster because they are smaller; the standard .45 ACP load is 230 grains compared to the standard 180 grain projectile in 10mm.

.45 ACP: Because They Don't Make A .46

When it was invented, the .45 ACP round was essentially .45 Colt with a shorter, rimless case to fit in a semi-automatic pistol. Initially it was devised for the Colt Model 1905, a test bed gun made by Colt (and even sold to the public) that was really an evolving design of handgun that Colt (and John Browning) wanted to sell to the armed forces and eventually became the .

What's the deal with the .45 ACP? It's a big, slow-moving bullet. The classic loading is a 230-grain ball that travels around 830 fps, carrying about 350 foot-pounds of energy. Not a screamer, but it hits hard for a semi-auto. It excels at penetrating soft tissues and creates marginally larger wound channels, even with hardball, than smaller rounds. With quality hollow points, expansion has long been held to be more reliable and more dramatic than with smaller rounds. The 185, 200 and 230-grain loadings are most common, but even lighter projectiles are made.

The .45 ACP round is very accurate in most handguns, which has made it popular as a target round. The chamber pressure - less than 23,000 psi in most chamberings - is very moderate among the popular defensive calibers as well, meaning that .45 ACP pistols will often have long service lives.

Recoil is ample but far from unmanageable, especially in a larger pistol. Many shooters find it comparable to a firm but steady push as opposed to the "snap" of the .40 S&W. It's a bit livelier in a compact.

As far as big-bore rounds go, it's a proven performer in self-defense applications with decades of military and police use. Compared to big-bore revolver rounds, it's cheap to shoot at less than $20 per box of 50 of modest quality hardball. It's accurate, and relatively easy to shoot among the large rounds. There is a lot to like.

Shooting a .45 might also mean shooting a 1911, which of course is the perfect gun one of the quintessential handguns of all time.

10mm: A Perfect 10

The 10mm round has an interesting history. It was devised by cutting down the .30 Remington rifle round - basically a retooled .30-30 for the semi-auto rifles of the day - and installing the .40-in diameter projectile from the .38-40, a zippy medium-bore pistol round from the late 19th century.

The round was imagined by Col. Jeff Cooper - he who wrote down the - and Dornaus and Dixon, a boutique gun company, cooked up the Bren Ten (an over-bored, dressed-up CZ-75) to shoot it with and Norma set about making the ammo.

The idea was a medium-bore cartridge with plenty of "oomph." The original specs were supposed to be a 200-grain bullet at 1,000 fps with 444 ft-lbs of energy. Norma got a 200-grain projectile up to 1,200 fps and 635 ft-lbs of energy back in the day. The standard load these days is 180 grains, moving somewhere between 1,100 and 1,300 fps, and carrying between 600 and 700 ft-lbs.

The 10mm Auto is the most powerful of the mainstream (keyword there) semi-auto rounds, with power levels on par with or exceeding the .357 Magnum, though the 10mm uses heavier projectiles that range from about 135 grains to 230 grains (165 to 200 are most common) though lighter loadings are available. Lower-recoil, lower-power loadings - often called "FBI loads" - are quite popular.

The 10mm is arguably the great all-arounder of handgun rounds. You can use a light loading for target shooting or carry, as a low-recoil 10mm load is literally a .40 S&W in a longer case.

You can also load it hot if you prefer a harder-hitting carry round. The 10mm is also one of the few mainstream semi-auto handgun rounds that's well-suited to hunting, as small to medium game (up to hogs and deer) are well within its capabilities. Then again, 10mm pistols are common packing guns in Alaska, with reports of efficacy on bears.

It's marginally cheaper than revolver rounds that have the same diversity (.41 and .44 Magnums, .45 Colt) and doesn't require an enormous frame. In essence, it may be the perfect auto-loading round...though it comes with some costs.

Is 10mm Better Than .45 ACP?

If you're weighing whether to get a 10mm vs .45 ACP pistol, think about what you want it for. It isn't that one is "better,": it's more that one is better for certain tasks than the other.

Granted, some people get obsessed with calibers; they just want a gun in a specific chambering and nothing else will do. If that's you, then get what your heart desires and have fun. That said, if there's a practical consideration being made, consider what you're getting the gun for.

If just punching targets, .45 ACP is better on paper. It's cheaper to buy (a box of 50 practice rounds goes for $30 or more in 10mm; in .45 ACP, about $17) and there are more guns offered in that chambering. It's also easier to shoot.

However, you get a bit more carrying capacity with a 10mm...a whopping 1 more round in single-stack magazines and 2 more in double stacks.

The 10mm is a right handful in a compact, so that's something to bear in mind for sessions. At that, darn few compacts are chambered for this round, so a 10mm CCW gun involves some very limited choices.

Compact .45 pistols, however, abound.

However, the 10mm cartridge, like the .357 Magnum, is something of a factotum among pistols. It's versatility is unmatched.

You can load it light for practice or even for carry, or load it hot and heavy for use in the backcountry or if you don't mind a stout carry load. The .45 ACP is simply not as diverse, and while a very capable defense round (actually one of the best) isn't as well-suited to the woods.

It's also worth noting, however, that you can get very close to 10mm power with .45 ACP+P loadings. There is also the matter of .45 Super, basically .45 ACP +P+, which requires the use of a stronger brass casing.

The .45 Super is right on 10mm's heels, matching it in lighter loadings such as the 185-grain loads but falls a little behind in terms of velocity and muzzle energy at the heavier end of what factory loadings there are. Handloads push the .45 Super further. As hot handloads of 10mm nips at the .41 Magnum's heels, the .45 Super comes close to the lower end of .45 Colt +P and .44 Magnum loads. The .45 Super uses the same projectiles as .45 ACP, yet still doesn't exceed 30,000 psi in most loadings and nearly replicates 10mm performance. It is likewise a worthy do-it-all round.

The point here is that .45 caliber semi-auto pistols ARE capable of the same power levels if that is one's concern. However, the potential has been lost as rounds like .45 Super, .451 Deltonics Magnum and .460 Rowland never really caught on commercially. While they proved itself in competition and a number of handgun hunters swear by them as hammers on small to medium game at close range, a following just never materialized.

In defensive shootings, both rounds have proven effective, but no handgun round has ever proven itself to be a reliable one-shot-stopper, even .44 Magnum. Only long guns are reliable one-shot stoppers and - no matter what anyone, anywhere says - the Judge is NOT, repeat not, a shotgun.

So, the 10mm is great if you want a gun that will do it all but don't mind some kick when shooting or when at cashier of the gun store. The .45, however, gives you more choice in pistols, costs less to run and is generally easier to shoot but is best suited to range work and carry.

Then again, find a few .45 ACP and a few 10mm pistols and shoot them. What you like most and shoot best is the one to acquire.