We’re just gonna come out and say this at the beginning. This post may ruffle some feathers. For some people, 1911s only come in one caliber: 45 ACP. Some others, though, believe that other calibers like 9mm or 10mm are superior for their 1911. We’re not here to answer which one of these calibers is the end-all, be-all best today. Instead, we’re going to look at 45 ACP vs 9mm vs 10mm for the 1911, the pros and cons of each, and which may be best for you.

45 ACP vs 9mm vs 10mm: Which is Best for the 1911?

There’s no “one size fits all” 1911 caliber. Instead, you’ll need to tailor which caliber you choose to what you’re trying to achieve. We’ll go a little more in-depth on the pros and cons of each 1911 caliber below.

1911 in 45 ACP: The Classic

When it comes to the 1911 platform, you could definitely do worse than 45 ACP. After all, it’s the original caliber that John Moses Browning created specifically for the 1911. It’s a big, heavy bullet that can transfer a lot of energy into its target. What’s more, most loads are naturally subsonic. That means 45 ACP is one of the best calibers if you want to add a silencer to your 1911.

However, it does have some downsides. The heavier faster bullet loads have a lot more recoil. So you either balance having a controllable, slow bullet or the most mass and velocity. Then, there’s the question of capacity. A standard magazine can only fit 7 or 8 rounds of 45 ACP into a 1911. And an extended magazine can only fit 10 rounds. That’s a pretty big pitfall when it comes to firepower.

1911 in 9mm: Great for Concealment

While 9mm is actually older than the 45 ACP, the 1911 never really became acquainted with the 9mm until the release of the Colt Commander 1949. Since then, 1911s have come in full sized, commander, and micro frame options.

Micro-1911s chambered in 9mm have been some of the top choices for fans of the platform who want to carry concealed. The Kimber Micro, for example, is chambered in 9mm and one of the smallest, lightest, and most concealable 1911-style guns in the world today. However there are some reliability issues in the older micro models.

In in their larger formats, many 9mm 1911s have increased firepower over their 45 ACP cousins with almost double the capacity and similar tried and true reliability.

1911 in 10mm: Heavy Firepower

Although they’re not as mainstream, you can still find plenty of 10mm 1911s. A 10mm 1911 will serve you well in a variety of roles. It’s a great gun for hiking, camping, or anything outdoors, since 10mm is rated for whitetail deer and is a common bear caliber with the right load. Some loadings start at the maximum velocity of .45 ACP and go up from there.

There are definitely a few downsides to a 10mm 1911, though. For one, they need to some sort of full-sized steel frame. They are going to be big guns, especially if you choose a double stack version, which can get particularly chunky. In addition, you’re going to be paying a premium for the ammunition. You’re going to have to get very well-acquainted with ordering ammo online.

There’s one thing for sure regardless of whether you choose 45 ACP vs 9mm vs 10mm for your 1911, though. You’re going to need a holster to carry it. And that’s one of Southern Trapper’s specialties. To learn more, explore our full selection of 1911 holsters here.

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