The .45 ACP (Automatic Colt Pistol) cartridge, also known as the .45 Auto, is a handgun cartridge designed by John Moses Browning in 1905 for the prototype Colt Model 1905. It was originally loaded with a 230-grain (15 g) bullet, launching it at 900 feet per second (270 m/s), with approximately 400 foot-pounds force (540 joules) of muzzle energy. While it has moderate power compared to more modern handgun rounds, it is known for its effectiveness in stopping adversaries and is a popular choice for self-defense and law enforcement applications.

History and Development

The .45 ACP cartridge was developed by the legendary firearms designer John Moses Browning. It was created as a compromise between the .45 Colt and .38 Long Colt cartridges, which were the standard sidearms of the US military at the time. Browning aimed to design a cartridge that offered better performance and stopping power than the .38 Long Colt while being more compact and easier to handle than the .45 Colt.

The .45 ACP cartridge was officially adopted by the US military in 1911, when it became the standard ammunition for the M1911 pistol. This pistol, designed by Browning, served as the primary sidearm for the US military for several decades and was widely used during World War I and World War II. The .45 ACP cartridge's performance and reliability in combat earned it a reputation for effectiveness and it became a popular choice for law enforcement and military personnel.

Ballistics and Performance

The .45 ACP cartridge is known for its moderate velocity and significant stopping power. It typically fires a heavy bullet, often weighing between 185 and 230 grains (12 to 15 grams), at velocities ranging from 850 to 1,100 feet per second (260 to 340 meters per second). The cartridge's design focuses on delivering a large diameter, heavy bullet that creates significant tissue damage upon impact, making it an effective choice for self-defense and close-quarters combat.

The .45 ACP cartridge's performance can be influenced by factors such as bullet weight, velocity, and design. Different bullet types, such as full metal jacket (FMJ), jacketed hollow point (JHP), and soft point (SP), can offer varying levels of penetration and expansion. Additionally, the use of specialized powders and bullet designs can further enhance the cartridge's performance, making it suitable for a wide range of applications.

Applications and Popularity

The .45 ACP cartridge has gained widespread popularity among firearms enthusiasts, shooters, and professionals due to its proven track record and reliability. It is commonly used for:

• Self-defense: The .45 ACP's stopping power and ability to incapacitate threats quickly make it a popular choice for personal protection.
• Law enforcement: Many law enforcement agencies around the world use firearms chambered in .45 ACP, especially for close-quarters combat and special operations.
• Military: While the .45 ACP has been largely replaced by other cartridges in military service, it still sees use in certain specialized roles and as a sidearm for select units.
• Competitive shooting: The .45 ACP is a popular choice for competitive shooting disciplines such as IPSC, USPSA, and IDPA, where its accuracy and controllability are highly valued.
• Hunting: While not typically used for hunting large game, the .45 ACP can be effective for small game and varmint hunting, especially with specialized loads.

Common Firearms Chambered in .45 ACP

The .45 ACP cartridge is compatible with a wide range of firearms, including:

• Pistols: The M1911 and its variants, such as the Colt 1911 and Springfield Armory 1911, are iconic .45 ACP pistols. Other popular choices include the Glock 21, Smith & Wesson M&P45, and SIG Sauer P220.
• Submachine guns: The .45 ACP is commonly used in submachine guns like the Thompson submachine gun, the Uzi, and the H&K UMP45.
• Carbines: Some carbines, such as the M1 Carbine and the M4A1 Carbine, can be chambered in .45 ACP, offering increased firepower and stopping power.

Ammunition Types and Loads

The .45 ACP cartridge is available in various loadings, each designed for specific purposes. Some common types include:

• Full Metal Jacket (FMJ): These rounds are designed for training and target practice. They offer good accuracy and reliability but may not expand upon impact.
• Jacketed Hollow Point (JHP): JHP rounds are commonly used for self-defense and law enforcement applications. They are designed to expand upon impact, causing greater tissue damage and stopping power.
• Soft Point (SP): SP rounds are similar to JHPs but with a softer lead core. They offer a balance between penetration and expansion, making them suitable for hunting and personal defense.
• Subsonic: Subsonic .45 ACP rounds are designed to be fired in suppressed firearms. They have a lower velocity and are often used for hunting or close-quarters combat situations where noise suppression is a priority.

Advantages and Disadvantages

The .45 ACP cartridge offers several advantages, including:

• Stopping Power: The large diameter and heavy weight of the .45 ACP bullet make it highly effective at incapacitating adversaries, making it a popular choice for self-defense and law enforcement.
• Reliability: The cartridge has a proven track record of reliability, especially in rugged conditions and under extreme stress.
• Accuracy: The .45 ACP is known for its accuracy, making it a preferred choice for competitive shooting and precision target shooting.

However, there are also some disadvantages to consider:

• Recoil: The .45 ACP cartridge generates significant recoil due to its heavy bullet and moderate velocity. This can make shooting more challenging for inexperienced shooters and can affect accuracy in rapid-fire situations.
• Ammunition Cost: .45 ACP ammunition tends to be more expensive than smaller caliber rounds, which can be a consideration for shooters on a budget.
• Bulk and Weight: Firearms chambered in .45 ACP are generally larger and heavier than those chambered in smaller calibers, which can affect concealment and portability.

Conclusion

The .45 ACP cartridge is a powerful and reliable choice for a wide range of shooting applications. Its stopping power, accuracy, and proven track record make it a popular choice for self-defense, law enforcement, and competitive shooting. While it does have some drawbacks, such as recoil and ammunition cost, the .45 ACP remains a favored cartridge among shooters and professionals alike.

What is the origin of the .45 ACP cartridge?

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The .45 ACP cartridge was designed by John Moses Browning in 1905 as a compromise between the .45 Colt and .38 Long Colt cartridges. It was adopted by the US military in 1911 and became the standard ammunition for the M1911 pistol.

What are the common firearms chambered in .45 ACP?

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The .45 ACP cartridge is compatible with a wide range of firearms, including pistols like the M1911 and its variants, as well as submachine guns and carbines.

What are the advantages of the .45 ACP cartridge?

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The .45 ACP offers excellent stopping power, reliability, and accuracy. It is a popular choice for self-defense, law enforcement, and competitive shooting due to its proven effectiveness.

What are the disadvantages of the .45 ACP cartridge?

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The .45 ACP cartridge generates significant recoil, which can affect accuracy and handling. It also tends to be more expensive than smaller caliber rounds and can add bulk and weight to firearms.

Is the .45 ACP cartridge still used by the military?

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While the .45 ACP has been largely replaced by other cartridges in military service, it still sees use in certain specialized roles and as a sidearm for select units.