Category: War
Few firearms have captured a nation’s spirit quite like John Moses Browning’s vaunted M1911. Rugged, reliable, cleverly engineered, and utterly lethal, this homegrown handgun is as American as baseball and blue jeans.
Yet, what would the legendary 1911 be without the potent and equally loved .45 ACP cartridge that Browning designed to go with it?
Even though it’s dubbed “the Lord’s caliber” thanks to its widespread popularity – and dare I say, righteous stopping power – I feel we’ve come to take the .45 ACP a bit for granted these days. Here’s a closer look at the story behind a pistol cartridge that helped define American small arms for over a century.
Table of Contents
.45 ACP History
Basic Ballistics & Specs
Pros & Cons
Final Thoughts
.45 ACP History
Developed in 1904, the story behind the .45 Automatic Colt Pistol (commonly .45 Auto and .45 ACP) is tied directly to America’s rise to prominence on the world stage. While the genius of the cartridge came squarely from the mind of Browning, it was actually the U.S. Army that determined the need for a .45-caliber bullet.
This owed much to two factors. First, America’s cavalry at the turn of the 19th century was on the hunt for something to replace the aging Colt Single Action Army revolvers chambered for the rimmed .45 Long Colt.
Meanwhile, a pressing second factor emerged from battlefield experiences during the Philippine-American War (1899-1902) and the Moro Rebellion (1902-1913) in the Philippines. American troops reported poor performance from their smaller .38-caliber revolvers during the campaign.
Frontline reports rolled in, describing harrowing hand-to-hand encounters with enemy fighters who simply shrugged off multiple hits from the U.S. Army’s rimmed .38 Long Colt, which was only recently adopted in 1892. This kicked off a hunt for something new and more powerful.
From the extensive Thompson-La Garde ballistic report in 1904, the army concluded its findings with the following determination: “After mature deliberation, the Board finds that a bullet which will have the shock effect and stopping power at short ranges necessary for a military pistol or revolver should have a caliber not less than 0.45.”
So, the stage was set, and the U.S. Army wanted a .45 caliber projectile similar to the .45 Long Colt already in use with the cavalry. It did not, however, want to return to a slow single-action-only revolver after its intense close-combat experiences in the Philippines.
At the time, Browning and Colt were already working on a .41-caliber prototype cartridge to go with a new semi-automatic pistol design from Browning. They responded to the new request for a .45-caliber cartridge by essentially redeveloping Browning’s handgun design and .41-caliber cartridge. This led to the Colt 1905, which was the first handgun chambered for the new .45 ACP.
Later U.S. Army trials led to the adoption of both Browning’s .45 ACP cartridge and 1911 pistol. Thus, one of the world’s most iconic caliber-gun duos of all time was born. The M1911 chambered for .45 ACP went on to become America’s longest-serving military handgun.
Its military record from 1911 until the mid-1980s made it a household name. But its performance on and off the battlefield made it a legend.
Basic Ballistics & Specs
Like the British .455 Webley, the .45 ACP was a straight-wall design that leaned heavily on the sheer mass of the bullet over velocity to do much of the downrange damage. Unlike the rimmed Webley casing and Browning’s earlier semi-rimmed .32 ACP, the new .45 ACP was a truly rimless cartridge.
Both the straight wall and rimless profile were meant to help the .45 ACP function specifically inside semi-auto firearms that fed from magazines instead of cylinders. At first, the Colt 1905 was tested with 200-grain bullets, but this was increased to 230 grains for what became the standard .45 ACP.
Before we dig into muzzle velocities and other data points, it’s worth highlighting that the U.S. military was very, very interested in terminal performance over simply specs. To that end, the Thompson-La Garde Tests from 1904 took a rather gruesome turn with testing on live animals.
This included a head-to-head comparison of the effects of close-range fire on living cattle with a .45-caliber projectile and a rising star in the 9mm Luger. Here are two brief but graphic excerpts of the results:
Blunt .45 Caliber: “9:46:30 A.M. Animal shot through lungs from left to right; fell to the floor at the sixth shot. Hemorrhage was free from one of the perforations in the right side. The animal was very much excited and kept jumping from side to side until she fell to the floor. Death occurred at 9:49 A.M.”
9mm Luger: “10:15 A.M. Animal was shot from left to right. There was an interval of one minute between the second and third shots, due to a hitch in the working of the pistol.
At 10:18:15 A.M., when the animal had been shot eight times, there was a short interval on account of reloading the magazine. Two shots were fired through the abdomen; at this time the animal was bleeding from the mouth.
After twelve shots had been fired the cow was still standing and had to be killed by the hammer. Ten shots were fired through the lungs and two through the abdomen in this experiment.”
As gruesome as the testing was, the clear impression left on the U.S. military was that the hefty .45 delivered with its heavy weight what the 9mm couldn’t with higher velocities. That terminal performance is still largely represented in the basic ballistics of modern 9mm and .45 ACP ammunition.
Here’s a quick comparison of basic, 124-grain 9mm FMJ and 230-grain .45 ACP FMJ.
You can also compare the .45 ACP stats from above to the rather anemic black-powder 150-grain .38 Long Colt, which offered velocities ranging from 650 to 750 fps. That put it at a mere 140 to 187 foot-pounds of energy. Even the switch to modern smokeless powder only bumped velocities to 750-800 fps. That left it at a relatively low 187-213 foot-pounds of energy.
For the modern shooter, there’s another benefit to the .45 ACP’s slower velocity. The increasing popularity of suppressors benefits from the subsonic speeds generated by the .45 ACP. Normal muzzle velocities for the .45 ACP generally fall between 800 and 900 fps, staying well below the speed of sound (1,125 fps at sea level in 68 degrees Fahrenheit).
Since this slow-flying bullet has enough mass to make up for its velocity, there’s a good reason .45 ACP is a popular suppressor round for handguns and pistol-caliber carbines. This quality was well known to gun designers in the 20th century, with firearms like the integrally suppressed British De Lisle commando carbine using the slow-moving .45 ACP as a quiet sentry killer in World War II.
Pros & Cons
Here are my top five pros and cons for the iconic .45 ACP. Keep in mind that modern specialty loads can vary greatly, so these are only based on the most general characteristics of the cartridge.
Pros:
- Strong terminal ballistics due to heavy weight
- Suppressor-friendly velocities
- Reliable semi-auto design
- Common and easily found caliber
- Over 100 years of proven performance
Cons:
- Large size lowers magazine capacities
- More expensive than 9mm
- Low velocities for longer ranges
- Usually more recoil than calibers like 9mm
- Heavier overall weights for carrying
Final Thoughts
The sheer number of 1911-type firearms still in production, with new variants arriving every year, is a solid testament to just how much America is still in love with Browning’s design. The .45 ACP remains a part of that legacy.
I have no doubt the caliber debate will continue to rage well beyond even the modern era’s “9mm vs. everyone else” trend. As for the classic .45 ACP, I can’t imagine it leaving the American marketplace in my lifetime. Anything is possible, but I think there are too many shooters who love the round for its history and performance to let it just fade away.
In fact, it’s still well-respected for its terminal performance and suppressor-friendly qualities. That has kept it as a go-to option for many law enforcement groups and private citizens. It’s also still a common feature inside Special Operations arsenals, even if its general military use has largely waned.
The “Lord’s caliber” gets the job done.
The Battle of Caloocan was one of the opening engagements of the Philippine–American War, and was fought between an American force under the command of Arthur MacArthur Jr. and Filipino defenders led by Antonio Luna in February 1899.
American troops launched a successful attack on the Filipino-held settlement of Caloocan on February 10, which was part of an offensive planned by MacArthur Jr. Occurring a few days after an American victory near Manila on February 4–5, the engagement once again demonstrated the military superiority that American forces held over the Philippine Revolutionary Army.
However, it was not the decisive strike that MacArthur had hoped for, and the war continued for another three years.
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Prior to the First World War, the nations of Europe made Hiram Maxim a very wealthy man. Maxim accomplished this with his machine gun, which was adopted by numerous nations in Europe and beyond. However, one of the major powers on the European continent wasn’t convinced — namely Austria-Hungary.
The reasoning isn’t fully clear, but one factor could be that the empire had a robust arms industry in Bohemia (the modern-day Czech Republic). Also, the fact that a member of the royal family, Archduke Karl Salvator, helped Colonel von Dormus of the Austro-Hungarian Army develop an early competitor to the Maxim Gun may have certainly played a role.
Salvator-Dormus M1893 Machine Gun
Patented in 1888, it has become known as the Model 1893 as that was when the weapon was first adopted by the Austro-Hungarian Navy (a year after Salvator’s death). It also came to be known as the Skoda machine gun by virtue of being manufactured at the Skoda Works.
With nearly a century and a half of hindsight in machine gun design looking back at it, the Salvator-Dormus 1893 machine gun is certainly an odd design — incorporating a mix of forward-looking elements with features that already seemed antiquated. It was chambered for the 8x50R smokeless cartridge and had an adjustable cyclic rate of fire, which could be set as low as 175 rpm or as high as 500 rpm.
It was fed from a unique fixed feed tower, which could be fed by an assistant gunner as the weapon was fired. The guns were reportedly reliable and could fire for upwards of nine minutes without stoppage. While it may have worked well as a naval gun, or in fixed positions, the Salvator-Dormus 1893 wasn’t considered ideal for infantry.
At least one saw use in combat during the Boxer Rebellion as it fired from the Austro-Hungarian battlecruiser when the warship was deployed to Peking. The U.S. military was offered a chance to test the Salvator-Dormus 1893 machine gun in China after the Boxer Rebellion, but only 600 rounds of ammunition were provided. The U.S. assessment was that it was reliable, but not able to endure the rigors of field use.
Some sources suggest a limited number may have been employed during the First World War, but that cannot be confirmed. One of the few surviving examples is in the collection in the Heeresgeschichtliches Museum — Militärhistorisches Institute (the Museum of Military History — Military History Institute) in Vienna, Austria.
Enter the Schwarzlose M.07/12 Heavy Machine Gun
The Austro-Hungarian military was far from satisfied with the Salvator-Dormus 1893 machine gun, but instead of adopting the Maxim, it again sought to forge its own path with help from the Prussian-born arms designer Andreas Wilhelm Schwarzlose.
He began development of a new machine gun in 1902 that employed a toggle-delayed lock, using a concept he first developed for a toggle-delayed pistol concept. As Schwarzlose had primarily been a handgun designer, it took several years for his design to be finalized.
Unlike the Maxim, the water-cooled machine gun had a fixed barrel, few moving parts, and a breach that was at no time truly locked, while it had a straightforward blowback mechanism. When the weapon fired, the rearward thrust of the exploding gases started the action opening at the same instant as it caused the bullet to move down the barrel. As it employed a very short barrel and a combination of extremely heavy recoil parts and springs, the weapon could employ a rifle cartridge. It had a cyclic rate of 400 to 500 rounds per minute, and it fired from a 250-round fabric belt.
First introduced in 1907, it featured a lubricating pump to lubricate each cartridge for ease of extraction, but it was subsequently rebuilt and a time extraction issue was addressed. That removed the need for the pump, but the machine gun still relied on a heavy bolt and a very strong recoil spring. It was also determined that the short barrel would result in a significant muzzle flash that could blind the gunner at night, and a cone-shaped dedicated flash hider was introduced to suppress the flash.
Designated the Schwarzlose M.07/12, it was employed by the Austro-Hungarian Army during the First World War, and like most of the machine guns of the era, it was used with a mount that weighed more than the actual weapon. However, that helped stabilize the weapon.
The M.07/12 was typically operated by a crew of three that included an NCO, a gunner who carried the weapon, and a third soldier who served as the ammunition carrier and loader. In practice, a fourth soldier was also employed to carry the tripod.
At the start of the war, the Austro-Hungarian Army fielded more than 100 infantry regiments, and each company included four platoons and a complement of 267 soldiers. However, the M.07/12 was relatively scarce as machine gun detachments were organized at the battalion level.
Austro-Hungarian Aviation Troops (k.u.k. Luftfahrtruppen) were equipped with the modified M.07/12/R16, an air-cooled variant. Due to a time delay between the trigger movement and the moment the bullet leaves the barrel, the weapon presented challenges in synchronizing it for use with fighters — and while the issues were eventually overcome, it was subsequently phased out of service as more suitable aircraft weapons became available.
Used by Austria and Beyond
The Schwarzlose M.07/12 was produced by Österreichische Waffenfabriks-Gesellschaft (OeWG), Steyr, and from 1914 to 1918 FGGY in Budapest. During World War I, Austria-Hungary also exported the M.07/12 to its Bulgarian and Ottoman Empire allies.
After the First World War, The Schwarzlose saw use with the militaries of the newly independent Czechoslovakia, Hungary, and Poland — as well as with the Austrian Army. The Netherlands and Sweden also acquired a number of the Austrian-designed machine guns, while a plethora of nations including Brazil, China, Colombia, Greece and Spain also adopted it in small numbers.
Beginning in 1924, the Czechoslovakian military converted the M.07/12 to 7.92x57mm and redesignated it the MG-7/24. Following the German occupation of Czechoslovakia, those weapons were subsequently employed by the German Wehrmacht and issued to the infantry divisions of the 5th and 6th Aufstellungswelle, which were mainly equipped with Czech weapons. At the end of the Second World War, the reserve stocks were issued to the Volksstrum (People’s Militia) forces. 
The M.07/12 remained in service beyond the Second World War and was used to equip the early Czechoslovakian Army in the early stages of the Cold War.
In 1931, the M.07/12s in service with Austria were modified to use the new 8x56R cartridge, which provided a significantly higher muzzle velocity (2,300 fps, instead of about 1,900-2,000 with the 8x50R). In addition, the Hungarian Army’s Schwarzlose machine guns were modified to use the 8x56mm 31.M “Hegyes” cartridge around the same time.
During the Second World War, the Schwarzlose M.07/12 was adopted by the same armies that it had been employed against during the First World War — namely Italy and Romania. The former adopted a number and used them in the campaign in North Africa.
The Romanian versions were converted to 7.62x54mmR — the same cartridge used by the Mosin-Nagant rifle. These also were fitted with a longer barrel and lengthened water jacket. However, those firearms appear to have seen little use in World War II — but according to some sources, the machine guns were used against German and Hungarian forces after the Kingdom of Romania left the Axis and joined the Allies as a co-belligerent. Thus some Romanian forces used an Austro-Hungarian machine gun against the Hungarians!
The Romanian versions had been sold as parts kits in the early 2000s, and a number were offered for sale as deactivated “dummy” or display guns. Yet, even these non-firing examples have become extremely rare in recent years.
Schwarzlose Machine Gun in Popular Culture
The M.07/12 has only been seen in a handful of films over the years, first appearing in the 1931 French-German film Mountains of Fire, which chronicled the fighting in the Alps during the First World War. More recently, it is among the firearms seen in a weapons museum in John Wick: Chapter 3 — Parabellum.
The Czech M.07/24 has also appeared in several movies, in some cases standing in for the M.07/12.
The M.07/12 remains an innovative firearm that saw use in the First World War and beyond.
In the late 1950s, there were basically two camps in the U.S. military on what the next service rifle should be — those who thought a service rifle should be made of wood and blued steel and wanted a modified version of the M1 Garand, and those who thought the future of the modern service rifle was with forged aluminum and polymer furniture.
While the 5.56mm AR-15 today is so common and accepted that it’s viewed as the “standard” in self-loading rifle design, it is easy to forget how revolutionary it was in its day. In the 1950s (and before the AR-15 was introduced), there was the AR-10 battle rifle.
This radical approach to military rifle design used forged aluminum receivers — an upper and a lower — that were mated with a stock made of polymer — essentially plastic. The caliber was 7.62×51 mm NATO, the same as the M14, but it used a gas-operated, straight-line rotating-bolt system, which offered less recoil than the M14. In addition, it employed a direct gas-impingement system. While it might have come from the same era as the M14, it seemed like it was from a different planet in those days. [Read more about the M14 history.]
The military bureaucracy was at a stalemate with its heels dug in. A lot was at stake, especially the lucrative government contract. Adding more drama to an already tense and passionate situation, the U.S. military saw the potential benefits of a high-velocity .22-caliber cartridge rather than the more ponderous — but capable — 7.62x51mm round.
To address this, the AR-10 was scaled down to the .223 cartridge and the AR-15 was born. However, the M14 community was still not budging. The M14 had the benefit of a proven design based on the Garand, as well as truly capable, if somewhat traditional, chambering. Despite the fact that the AR-15 and the 5.56×46 mm NATO cartridge had shown great promise in initial testing, the U.S. military’s choice of the M14 over the AR-10 (as well as the FAL) had solidified the wood and steel rifle in the role of primary service rifle for the United States military — for now.
However, the “aluminum and plastic” upstart would soon gain the upper hand. As is well known, the AR-15 platform eventually prevailed. So, let’s consider that journey.
In hindsight, it was easy to see that the AR-15 would ultimately prevail. Prior to the AR-15 becoming the M16, other factors shaped the evolution of our approach to warfare and the tools used to fight. Let’s take a 10,000-foot view of defense policy in the post-WWII era.
Cold War, Nuclear War, or Guerrilla Warfare?
After WWII and the first use of nuclear weapons, the role of the infantry soldier was thought to be played out in a nuclear battlefield. The nuclear arms race post-WWII had both sides rethinking what a post-nuclear war landscape would look like.
Thankfully, the Cold War-era struggle did not take the form of an atomic mushroom cloud. Counterinsurgency was the new strategy in the unique form of warfare that developed with two opponents armed to the teeth with nukes. Since direct combat was not feasible (as it would effectively end our civilizations), proxy warfare became the norm in hotspots worldwide.
America’s approach was to help these countries fight communism by arming, teaching, and supporting our allies in limited wars in their own nations. Hence, rather than atomic stockpiles of weapons, an old-fashioned arsenal of specialized small arms became the focus. Throw in a few advisors for training, and you have a recipe for the Vietnam War.
Project Agile Is Approved
While the Advanced Research Projects Agency (or “ARPA”), tucked under the broader Defense Department umbrella, was originally organized to research ballistic missiles, in 1961, the Kennedy administration — with an interest in supporting our foreign allies in limited wars to stop communist aggression — approved Project Agile.
Project Agile was designed to help remote areas of the world with counterinsurgency action against communist insurgents. Two areas, both in Indochina, were identified as under threat to Communist aggression. One was in Bangkok, and the other was in Saigon.
The average height of a Vietnamese soldier was five feet, and he weighed about 90 pounds. The ARPA was convinced by the original manufacturer of the AR-15 that the gun had a great deal of potential as a rifle for Vietnamese fighters since it was lightweight, capable and soft recoiling.
ARPA requested AR-15s for this effort, only to be denied because there were plenty of M2 Carbines in storage that could be issued without spending budget on new guns.
The M2 Carbine was also lightweight and ideal for operators with small statures. The ARPA reintroduced its request and suggested that a limited number of AR-15s be used. They settled on asking for 1,000 rifles to only be used in Vietnam (and not Thailand), and the rifles would be tested against the M2 Carbine.
There were many other subprojects under Project Agile, such as ones that dealt with communications and logistics, as well as planning. However, the ARPA report for the AR-15 was titled “Task 13A” and compared the M2 Carbine to the AR-15 “to determine which is more suitable replacement for other shoulder weapons in selected units of the Republic of Vietnam Armed Forces (RVNAF).”
The Result
I don’t need to tell you the outcome. You already know the AR-15 performed best with the “small stature of the Vietnamese soldier…”. We all know that the taller U.S. advisors liked how the new rifle performed, too. While the test helped ARPA in one of its many projects assist counterinsurgents by confirming the superiority of the AR-15 to the M2 Carbine, it also proved the readiness of the AR-15.
Analysis of the AR-15 from both U.S. Advisors and Vietnamese commanders reported the AR-15 as “extremely favorable.” The lethality of the .223 round proved to be extraordinary. Users had a high respect for the AR-15 and preferred it to all other firearms available.
The first AR-15s in country did not have a forward assist, which is how the Air Force (the first adopter of the design) wanted the gun. The Army, however, insisted on a forward assist and originally designated the rifle the XM16E1; after the details were worked out, it was designated the M16A1.
Conclusion
The testing under Project Agile was the first time the rifle was used in Vietnam. In 1964, America’s broader involvement in Vietnam was officially begun with Congress passing the Gulf of Tonkin Resolution, which authorized direct U.S. military involvement in the nation. The rest is history.