The History of .45 ACP: From Inception to Modern Day

— Jason MosherCADRE Dispatch

The .45 ACP holds a prominent place in the history of firearms and ammunition. Known for its stopping power and effectiveness, this round has become a staple in both military and civilian use.

The story of the .45 ACP (automatic colt pistol) caliber begins with the genius of John Moses Browning, a legendary firearms designer whose innovations shaped the landscape of modern weaponry.

It came about because of the need for a more effective cartridge, leading to the development of the iconic M1911 pistol. This pistol, chamber in .45 ACP saw use in WW1, WWII, Vietnam, and other wars and conflicts.

Over the years, other firearms have been chambered in .45 ACP, maintaining its popularity and relevance. Let’s explore the origins of the .45 ACP caliber, its development, and its enduring legacy.

John Moses Browning: The Inventor

John Moses Browning. (Public Domain)

John Moses Browning was born on January 23, 1855, in Ogden, Utah. From a young age, he exhibited an exceptional aptitude for mechanics and engineering, often helping in his father’s gunsmith shop. Browning’s innovative spirit led him to create his first firearm at the age of 13, a single-shot rifle. While this got him in a little bit of trouble with his parents, it set the stage for a prolific career in firearms design.

Browning’s contributions to firearms are vast and varied. He held 128 firearm patents, and his designs include some of the most famous and widely used guns in history. These designs include firearms such as the M1911 pistol, the Browning Automatic Rifle (BAR), and the M2 Browning machine gun.

Browning revolutionized firearms technology, emphasizing reliability, ease of use, and effectiveness. There simply wasn’t anything else like Browning’s inventions.

The Birth of the .45 ACP Cartridge

Browning’s .45 ACP was the result of the U.S. military’s need for a more effective sidearm and cartridge.

In the late 19th and early 20th centuries, the military primarily used the .38 Long Colt cartridge. However, during the Philippine-American War, the .38 Long Colt proved insufficient in stopping Moro warriors in close combat. This inadequacy led to a demand for a more powerful round with better stopping power.

In 1904, the U.S. Army commissioned tests to find a more effective cartridge. The tests concluded that a larger, heavier bullet was necessary to provide the stopping power required by the US Military. Browning, already a renowned firearms designer, took on the challenge.

He developed the .45 ACP cartridge, a rimless, straight-walled cartridge with a bullet diameter of .451 inches and a case length of .898 inches. The cartridge delivered significant stopping power while maintaining manageable recoil for the shooter.

The M1911

Browning’s .45 ACP cartridge needed a firearm that could effectively utilize its potential. Browning designed the M1911 semi-automatic pistol to fire the .45 ACP round.

Brownings .45 ACP
Browning’s .45 ACP was designed for the 1911 pistol but has since been used in a wide range of other firearms.

The M1911 featured a single-action, recoil-operated design with a seven-round magazine. Its robust construction and reliable performance made it an ideal sidearm for military use.

It was March 15, 1911, when Colt, using Browning’s design, went toe-to-toe with Savage for a final battle of handguns. More than 6,000 rounds were fired through each gun. During Savage’s test, the gun malfunctioned 37 times. This was not bad for handguns at that time. But when Colt fired the 1911, it went through all 6,000 rounds without a single malfunction which is impressive even for today’s standards.

It goes without saying, the U.S. military adopted the M1911 pistol, and it soon became standard issue for all U.S. soldiers. It didn’t take long for it to gain a reputation for its effectiveness and reliability. As mentioned above, it saw extensive use in World War I, World War II, the Korean War, and the Vietnam War.

Government 1911.
A lot of companies are now making the legendary 1911 pistol.

Historic Guns Chambered in .45 ACP

Since then lot of other firearms have been chambered in the infamous .45 ACP. While the cartridge may have risen to fame from the barrel of the 1911 pistol, it holds its own place in history as well.

Here’s a quick look at some of the most notable guns that have fired the .45 ACP.

Colt M1911

The original platform for the .45 ACP, the M1911 remains one of the most iconic and widely used pistols in history. Its design has influenced countless other firearms, and modern versions of the M1911 are still produced today.

Thompson Submachine Gun

Tommy gun.
The M1 Thompson or “Tommy Gun” was chambered in .45 ACP.

Known as the “Tommy Gun,” this firearm gained fame during the Prohibition era and World War II. The Thompson Submachine Gun’s use of the .45 ACP cartridge provided excellent stopping power in a fully automatic weapon.

Smith & Wesson Model 625

This revolver is chambered in .45 ACP, utilizing moon clips to hold the rimless cartridges. The Model 625 combines the power of the .45 ACP with the reliability of a revolver design.

Glock 21

glock 21 gen 5
The Glock 21 brought us a big bore option.

A modern semi-automatic pistol, the Glock 21 is known for its reliability and ease of use. Chambered in .45 ACP, it offers a high-capacity magazine and is popular among law enforcement and civilian shooters.

Heckler & Koch HK45

Developed as an improvement over the earlier USP45, the HK45 is a robust, accurate, and reliable pistol chambered in .45 ACP. It features an ergonomic design and is used by various military and law enforcement agencies.

Modern Guns Chambered in .45 ACP

The .45 ACP remains a popular choice for many shooters today. While its popularity has diminished some, it maintains a dedicated following. Because of this following, gun manufacturers have not abandoned the cartridge.

There’s a long list of modern-day firearms chambered in .45 ACP today. Here are a few examples:

Springfield Armory XD(M) 45

This modern polymer-framed pistol offers excellent ergonomics, a high-capacity magazine, and reliable performance. It is a popular choice for both self-defense and competitive shooting.

Sig Sauer P220

Known for its accuracy and reliability, the P220 is a classic design that has been updated with modern features. It is widely used by law enforcement and military personnel around the world.

Ruger SR1911

A modern take on the classic M1911 design, the SR1911 offers the timeless appeal of the original with modern manufacturing techniques and materials.


This modern tactical pistol features a threaded barrel for suppressor use, a polymer frame, and a high-capacity magazine. It is built for both military and civilian use.

Kimber Custom II

A high-quality 1911-style pistol, the Kimber Custom II is known for its accuracy, reliability, and craftsmanship. It is a popular choice for competitive shooting and personal defense.

The Enduring Legacy of the .45 ACP

Time is the ultimate test, and there’s no doubt, the .45 ACP cartridge has stood this test and prevailed. From Browning’s first test fire to modern-day firearms, it has maintained its popularity and relevance for over a century.

John Moses Browning’s legacy is much more than this cartridge alone. But out of all his inventions, the .45ACP and 1911 pistol are undeniably one of his all-time greats.

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