Complete Guide to 1911 Calibers
The iconic 1911 pistol chambered in .45 ACP is the gold standard for 1911 enthusiasts dedicated to John Browning's original design. However, .45 ACP is not the only cartridge available on today's market, and it may not be the best choice for your specific needs. 9mm, .40 S&W, and .22 LR are among the other cartridges available. As you continue reading our complete guide to 1911 calibers and cartridges, you’ll discover several common and uncommon 1911 calibers and which is right for your situation.
What Caliber Is the Original 1911?
The original 1911 caliber is .45 ACP. John Browning designed the 1911 in response to the U.S. Army’s need for a more powerful sidearm than the standard .38 caliber revolvers. Even though the .45 ACP and 1911 are over 100 years old, they remain the most popular choices because of their excellent stopping power and nostalgic appeal.
All Available 1911 Calibers
Below you’ll find a list of the most common 1911 calibers and a few that aren’t so common.
1. .45 ACP (Most Common)
The .45 ACP is the gold standard because it’s the original cartridge the 1911 was intended for, so it has that traditional 1911 feel and shooting experience. The .45 ACP 1911 has proven itself in self-defense situations (solid ballistics, with a muzzle velocity of ~850 fps and a muzzle energy of ~400 ft-lbs), and .45 ACP ammo is readily available. However, it has a lower capacity (7-8 rounds) and heavier recoil. So there are some downsides to the .45 ACP. For die-hard nostalgic 1911 shooters, there is no other option.
2. 9mm (Growing in Popularity)
The 9mm 1911 is another popular choice for enthusiasts not stuck in traditions. Many shooters appreciate that it has an increased magazine capacity (10-12 rounds), less recoil, and less expensive ammo than the traditional .45 ACP. Modern 9mm ammo performs ballistically very well, with a muzzle velocity of ~1,150 fps and a muzzle energy of ~350 ft-lbs. However, 9mm doesn’t have as much stopping power as .45 ACP.
3. 10mm Auto
If you’re looking for the perfect balance of capacity and raw power, go with a 10mm Auto 1911. It’s often used for hunting and outdoor range shooting. The 10mm Auto cartridge is not for the faint of heart, as it delivers serious recoil along with its stopping power. If you choose the standard model, you’ll get a mag capacity of 8 rounds, but you can double that to 16 powerful rounds with a double-stack frame and magazine.
4. .38 Super
Though the .38 Super has been around for many decades, it’s not nearly as popular as many of the other options on the list because of limited and expensive ammunition. However, the .38 Super 1911 is a favorite among competitive shooters for its high velocity, flat trajectory, reasonable recoil, and good penetration. Another reason it’s best for USPSA/IPSC competitions is that it offers a higher magazine capacity than .45 ACP. If you enjoy reloading and competition shooting, then a 1911 chambered in .38 Super might be the perfect combination.
5. .40 S&W
It’s no surprise that the 40 caliber 1911 is an excellent middle-ground. It’s a little less common than 9mm and .45 ACP, but more readily available than .38 Super. It has a little more recoil than the 9mm, but slightly more stopping power. The 40 caliber 1911 is a favorite among CCWers.
6. .22 LR
The .22 LR is the most popular cartridge in the world, so it’s no surprise that a .22 LR 1911 would be a favorite of many shooters. It’s great for training new and experienced shooters, keeping your skills sharp, and just plinking at the range. .22 LR ammo is inexpensive, but it lacks the necessary stopping power to be a reliable self-defense or hunting cartridge.
Rare Calibers: .357 SIG, .400 Cor-Bon
A couple of less common 1911 cartridges are the .357 SIG and .400 Cor-Bon. If you’re not a fan of the 10mm Auto, but still want to load a powerful cartridge into your 1911, then the .357 SIG and .400 Cor-Bon are viable options.
1911 Caliber Comparison Table
Caliber | Capacity | Muzzle Velocity | Muzzle Energy | Recoil | Ammo Cost | Best For |
.45 ACP | 7-8 rounds | ~850 fps | ~400 ft-lbs | ~8 ft-lbs | $0.35 to $2 | All Around/ Nostalgia |
9mm | 10-12 rounds | ~1,150 fps | ~350 ft-lbs | ~4 ft-lbs | $0.19 to $2 | Recoil Sensitivity / Higher capacity |
10mm Auto | 8 rounds (single-stack) 16 rounds (double-stack) | ~1,250 fps | ~600 ft-lbs | ~11 ft-lbs | $0.38 to $2.05 | Hunting |
.38 Super | 9 rounds (single-stack) 24 rounds (double-stack) | ~1,400 fps | ~400 ft-lbs | ~5 ft-lbs | $0.50 to $2 | Competition |
.40 S&W | 8 rounds | ~1,100 fps | ~400 ft-lbs | ~6 ft-lbs | $0.28 to $2 | Compromise between capacity and power |
.22 LR | 10 rounds | ~1,200 fps | ~150 ft-lbs | ~1 ft-lb | $0.05 to $0.55 | Training and target practice |
.357 SIG | 8 rounds | ~1,300 fps | ~550 ft-lbs | ~7.5 ft-lbs | $0.57 to $2 | Balance of recoil and power |
.400 Cor-Bon | 7 rounds | ~1,350 fps | ~575 ft-lbs | ~8 ft-lbs | $1 to $2 | Balance of recoil and power |
How to Choose the Right 1911 Caliber
Still unsure what 1911 cartridge is best for you? The criteria I used to choose my 1911 calibers are listed below.
For Self-Defense
For home and self-defense, I would choose from 9mm, .40 S&W, and .45 ACP. There are plenty of self-defense ammo options for each of these cartridges, and they’re readily available. The 9mm will have a higher capacity and more controllable firearms, but the .45 ACP will have the most stopping power. The .40 S&W will sit in the middle in terms of capacity and power.
For Competition
If I were competing with a 1911, I would choose the .38 Super for USPSA/IPSC matches, the 9mm for USPSA production matches, and the .45 ACP for traditional divisions.
For Training/Practice
If you’re looking for an inexpensive way to train on a 1911, get one chambered in .22LR because the ammunition is so much more affordable than other cartridges. The 9mm also has less expensive ammo than most other options, and it can double as a viable self-defense option with a simple switch of ammo.
For Hunting/Outdoors
The 10mm is the best option for hunting as it’s powerful and offers better penetration than other 1911 cartridges. It’s often a favorite in bear country as a secondary firearm.
Frequently Asked Questions
What is the best caliber for a 1911?
The .45 ACP is the best caliber for a 1911 for tradition and power. The 9mm is the best caliber for a 1911 for capacity and cost.
Can you change calibers on a 1911?
Yes, you can change calibers on a 1911 by changing the barrel and magazine (some calibers are easier than others).
What's the difference between 9mm and .45 ACP in a 1911?
The difference between 9mm and .45 ACP in a 1911 is capacity vs. power trade-off. The 9mm holds 3-4 more rounds while the .45 ACP has more stopping power.
Are all 1911s .45 caliber?
No, not all 1911s are .45 caliber. Modern 1911s are available in multiple calibers.
Parting Shots: 1911 Calibers
Now that you know what calibers a 1911 is available in, you can make a wise decision. The .45 ACP is still the gold standard. The 9mm offers practical advantages, such as higher capacity and lower recoil. The choice ultimately depends on your preferences and intended use. Check out our guide to the common 1911 makers for 1911 brand recommendations.
Growing up in rural Oklahoma has given me the privilege of hunting and shooting my entire life. I built a shooting range to sight-in my deer rifles and send some lead downrange with my pistols.
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Changing barrel and magazine from a 45.ACP to a 9mm caliber. Does the ejector need to be change also? I read somewhere that the ejector needed to be changed.
GUncrafter makes the 50GI