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The 10mm vs 45 ACP debate has been around for a long time, but with the resurgence of interest in the 10mm Auto cartridge, it is now raging again. For about 70 years, the 45 ACP was the undisputed king of the hill among semi-auto pistol cartridges. However, with the introduction of the 10mm Auto cartridge in 1983, the great 45 ACP began to lose some of its luster with shooters. Now, many shooters believe the 10mm Auto is the king of pistol cartridges. Sure, you can find 357 and 44 Magnum auto-pistols, but these are unwieldy contraptions with limited practical applications, and both the 10mm and the 45 are popular in the 1911 pistol, as well as other models. Both are also highly useful cartridges, and they have very interesting origins. So, let’s take a close look at 10mm vs 45 ACP, and drill down on which is best suited for you needs.
10mm vs 45 ACP: Table of Contents
The 45 ACP/45 Auto
The 10mm Automatic
10mm vs 45 ACP: Ballistic Comparison
10mm vs 45 ACP: Recoil
10mm vs 45 ACP: Best Loads
Which is Better: Application Is the Key
Related: 10mm vs 9mm: Which Handgun Should You Pack?
The 45 ACP
We’ll start with the 45 ACP, but the first thing we want to do is get the name right. Although many shooters refer to the cartridge as the 45 ACP (45 Automatic Colt Pistol), according to SAAMI (Small Arms and Ammunition Manufacturer’s Institute), the correct name for the cartridge is the 45 Automatic and the correct abbreviation is 45 Auto. Today, both names are used interchangeably. Regardless, it is one of the most iconic of all pistol cartridges and John Browning designed it in 1904. It won its fame in the Colt 1911 pistol, which served the United States military until the 9mm Beretta was adopted in 1984. However, the 45 Auto remained in service long after that with some military organizations that were not overly enthralled with the 9mm.
The 45 Auto is generally loaded with bullets ranging in weight from about 160 to 255 grains. It’s respected for packing a good punch without a lot of recoil, and it’s revered by many. The large diameter of the 45 Auto cartridge, however, limits capacity in pistols with common-sized grips that are designed to be manageable by the most shooters. Though the 45 has seen some use by law enforcement, most of its admiration has come from the military and civilian shooters.
The 10mm Automatic
Some give credit to former Marine and Gunsite Academy founder Jeff Cooper for the development of the 10mm Automatic/10mm Auto. The truth is, Cooper is mostly responsible for promoting the notion that a 200-grain 0.40-caliber bullet at about 1000 fps would be a better option for personal protection – especially at distance – than the 45 Auto. Cooper consulted on the development of the 10mm, but the result – first offered by Norma in 1983 – was a bit more powerful.
The 10mm Auto really began to gain popularity in 1987 with Colt’s introduction of the 1911 Delta Elite pistol, but then it really took off because of its use in the Miami Vice television series and when the FBI selected it for duty in 1989. The FBI ultimately settled on the 40 S&W, often called the 10mm short, and they have now reverted to the 9mm. For about two decades, the 10mm had what might be considered a cult-like following and then its popularity seemed to wane. Recently however, interest has dramatically spiked, partially from increased interest in the cartridge for handgun hunting and predator defense, and because of more factory ammunition options.
10mm vs 45 ACP: Ballistic Comparison
A lot of factors contribute to ballistic performance, but one of the most important is pressure. Original 45 Auto ammunition was loaded to an average pressure of 21,000 psi. Amped up 45 Auto +P ammunition is loaded to 23,000 psi. The 10mm Auto, on the other hand, is loaded to a maximum average pressure of 37,500 psi. That’s substantially more power/pressure and is the reason a 200-grain bullet from a 10mm Auto has about a 20 percent velocity advantage over the same weight bullet from a 45 ACP. Here’s a breakdown.
More velocity also equates to more kinetic energy. Now, kinetic energy alone is not a valid representation of terminal performance, but it does offer a comparison of power, or you might say, the ability of the bullet to do work after impact. When you compare the fastest 200-grain bullets from the 10mm and the 45 ACP, you’ll see that the 10mm bullet will have an energy advantage of about 195 foot-pounds (44 percent) at the muzzle. This seems substantial but remember, from a terminal-performance standpoint, bullet diameter matters too. The 45 Auto has about a 12 percent advantage in unfired bullet diameter, and generally, even more with bullets that have fully deformed after impact. Ballistically, it seems clear that the 10mm Auto has the advantage, but ballistic superiority is not always the most important thing. Recoil matters too.
10mm vs 45 ACP: Recoil
My testing has shown that a 20 percent increase in recoil impulse will generally increase the time it takes you to fire two accurate shots—as fast as you can—by about the same percentage. This can matter a great deal or not at all. If you’re in an action-pistol competition, the harder kicking handgun will limit your ability to deliver fast and accurate shots. The same would apply if you are trying to brain a charging brown bear. This is one reason few shooters compete with 10mm pistols. On the other hand, if you’re deer hunting, that first, single shot is really the one that matters. Additionally, most of the shooting most of us do is for fun and its harder to have fun with a pistol that is less comfortable to shoot.
Related: 9mm vs 40 S&W: Which is Better?
Which is Better? Application Is the Key
History, ballistics, and recoil aside, it’s what you want to do with a handgun that really determines which cartridge is best. If you want to shoot recreationally, the 45 ACP is more comfortable, and ammo is more affordable, too. On the other hand, if you want to hunt big game, the 10mm hits harder and shoots flatter. If general-purpose self-defense is your primary concern, there are more 45 Auto ammo options, and its lighter recoil will allow you to shoot multiple shots faster.
Many believe that the 10mm Auto has the advantage when used for backcountry survival or bear defense. This seems logical given its ballistic advantage. However, if the right loads are used the 45 Auto might be the better choice. Both the 10mm and 45 Auto will penetrate enough, but the 45 Auto has a slight advantage because of its larger diameter bullet. With non-deforming hardcast bullets, both can penetrate deeper than a 180-grain Barnes Triple Shock bullet fired out of a 30-06 rifle!
Best Loads for Both
There are a lot of opinions when it comes to the best 45 Auto load for self-defense. Some like the heavy, slow moving bullets, and others prefer the faster moving, lightweight bullets. I tend to like the heavier bullets, but with one exception. The 160-grain Barnes TAC-XP bullet seems to be both velocity and barrier blind. It has no trouble defeating intermediate barriers like wall board, and the bullet will fully deform over a wide velocity range. I liked it so much I had Doubletap Ammo create a load for me with a velocity of 1050 fps, which makes it reasonably comfortable to shoot. It’s called the “Mann Load.”
If you want one of the best personal defense loads for the 10mm Auto, and you don’t mind the stiff recoil, you’ll be hard pressed to find a load that will outperform the 200-grain Federal HST load. HST bullets are very popular with law enforcement because of how well they perform in the FBI handgun ammunition test. This load has a muzzle velocity of more than 1100 fps and generates more than 500 foot-pounds of kinetic energy at the muzzle.
When it comes to a load for the 10mm or 45 Auto that needs to be capable of stopping a big and brown, pissed off bear, the best option I know of for both cartridges is the Buffalo Bore Outdoorsman loads. The one for the 45 Auto is a +P load that uses a 255-grain hardcast bullet at 925 fps, and the one for the 10mm uses a 220-grain hardcast bullet at 1200 fps.
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