History of the .45 ACP Cartridge

By David Tong
Background, history, features and load data on the .45 ACP cartridge.

Team Never Quit 45 ACP 155gr Frangible Ammo
Team Never Quit 45 ACP 155gr Frangible Ammo @ Brownells ; http://goo.gl/9Lc6m1
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USA -(AmmoLand.com)- In U.S. military circles for over one-hundred years; from the onset of the Civil War all the way to today, there has been a tendency to prefer a large diameter bore, subsonic pistol cartridge if we are required to use a non-expanding bullet in the round.

While the old cap-and-ball 1860 Colt Army and 1873 Single Action Army used a .44” round ball, and a 255gr .454” flat-tipped conical lead bullet, respectively, neither projectile was designed to expand, and what little expansion occurred was because of their soft cast lead construction rather than by design.

The Army Ordnance folks around the beginning of the 20th Century had seen the failures of round-nosed, full-metal jacketed bullets in the British .303 rifles, and our own .30 U.S. Government (aka “.30-40 Krag”) in stopping a determined armed assailant.

As a result of numerous instances of the new .38 service pistols being ineffective the US Army was forced to hastily re-issue mothballed Single Action Amy .45 Colts.
As a result of numerous instances of the new .38 service pistols being ineffective the US Army was forced to hastily re-issue mothballed Single Action Amy .45 Colts. IMG : historicalfirearms.info

They reasoned that since their .38 Long Colt Model 1892 revolvers had shown similarly poor results, and the re-issuance of the .45 SAA (Single Action Arm) into combat had added to the eventual defeat of the Philippine Moros, our military review board sought to adopt another large bore handgun. The British too paralleled this thought process, and as early as the mid-1880s they had already started issuing some of the first .455 Webley revolvers as a result.

The advent of smokeless powder, its clean burning, and the copper jacketed bullet meant that Colonel John Thompson and Major Louis La Garde’s study of the effect of handgun bullets in 1904 suggested, via an observation of momentum transfer (motion of hung sides of beef, human cadavers), as well as some shooting tests on live cattle, that “calibers no less than .45” were the way to go.

. 45 ACP Cartridge

Several cast . 45 ACP cartridge s
Several cast . 45 ACP cartridge
Vintage .45 Caliber Pistol Ball Ammo M1911
Vintage .45 Caliber Pistol Ball Ammo M1911

By the middle of the first decade of the 20th Century, Colt was developing, along with the genius designer of most of their handguns, John Browning, a .45 cal. semi-automatic pistol. While the original development utilized a 200gr bullet at approximately 900 feet per second in 1906, the Ordnance Department subsequently desired a cartridge that approximated the old .45 Colt revolver cartridge in power, while being shorter in length than the substitute standard .45 S&W Schofield round.

Thus, the 230gr RN FMJ bullet at 850 fps nominal speed was created, and it found a home in the concurrently developed Colt Model 1911 pistol, the longest serving pistol of any military force to the best of my knowledge, some 75 years of official issue.

The . 45 ACP cartridge has a very slight taper, some 0.003” from case head rim to case mouth, so it can be considered a straight case for feeding purposes. The cartridge has changed only in the adoption of non-corrosive primers and different powder formulations in the mid-1950s, and it was known as “Cartridge, Ball, M1911, Cal. 45” for its entire military service life.

In the civilian world however, it has remained as popular as ever. Due to the existence of new generation jacketed hollow point bullets, it still retains its terminal ballistic advantages of expansion and consistent penetration compared to smaller bore diameter offerings. A recent detailed study indeed illustrated that the Federal HST 230gr standard pressure rounds offer 16” of penetration and consistent 0.85” of controlled expansion with no bullet fragmentation in an unofficial “FBI heavy clothing test” into simulated ballistic gelatin.

Springfield Armory XDM Threaded Models in .45 ACP and 9mm shown here with a SilencerCo Osprey (top) and SilencerCo Octane (bottom)
The .45 ACP operates at a very low 21,000 copper units of pressure, it has no supersonic crack, and is therefore nearly ideal for use with a suppressor.

One other thing that is not mentioned much is that its stopping power is achieved without superior “sectional density,” high pressure, or high velocity. It operates at a very low 21,000 copper units of pressure, it has no supersonic crack, and is, therefore, nearly ideal for use with a suppressor. The recoil, while “there,” is more a push than a quick snap, while controlled-pairs shooting aimed rapid-fire are pretty easy to do out to ten yards and can usually be within an inch of each other. I’ve done it, and I’m just not that great a shot.

Moreover, the . 45 ACP cartridge has long borne the brunt of technical development as a precision target shooting round as well as being a supremely controllable defense round. In both the original 230gr RN,FMJ format for “hardball matches,” as well as reduced weight 185gr and 200g target matches, it remains one of the most accurate service pistol rounds extant. When a tuned 1911 style pistol is coupled with this ammo, it’s little surprise to me that retired USMC Gunnery Sergeant Brian Zins has triumphed at the National Matches at Camp Perry, Ohio as overall champion a record twelve times from 2002 through 2013. His accomplishment will likely never be equaled. (He’s also a really nice guy whom I met at SHOT show in 2013).

Brian Zins Wins 11th NRA National Pistol Championship
Brian Zins Wins 11th NRA National Pistol Championship

To this day, elite agencies such as LAPD, SWAT, FBI, HRT, and USMC SF still use the 1911 and its revered .45 ACP cartridge. It is an American Classic.

. 45 ACP Cartridge Ammuntion Loading Data

.45 ACP Ammunition Resources:


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110 years ago, my grandfather was in the army during the Moro Insurrection. Islamic terrorists would drink Mazhnun, (means MADNESS in Arabic) high grade Filipino Hashish (root from Arabic word Assassin) mixed with low grade rum. THC made them paranoid & Alcohol made them Angry. They would swoop down from the BOONDOKs (hills) swinging a razor sharp double edged sword called a CRIS. The attacks were called RUNNING AMOK (the first drive-bys) The Spaniards called them “Los Jurantados.” They would rape & pillage the women in the Vesayan Villages and also attack the American soldiers. The US Side arm was… Read more »

Deplorable Bill

Good work. There’s more. The U.S. Army actually tested this round and pistol on cadavers and volunteers among the condemned who had been promised freedom if they survived. Most didn’t.

Best combat pistol ever made. When you get good at running one it’s not beatable. I was on the Fort Lewis pistol team and then compeated ipsc and IDPA for 3 decades. Carry one daily.

Arm up and carry on

Roy F. Wilt

You’ll notice that they don’t show any survivors of being shot with a 45 acp. That’s because if you get hit in the center mass with one, you are DEAD!!!!!!!!!!!!!!!!!!!!!!!!!

Don McDougall

Great article. Thank you.


Just last week I got the M1918 out and did some target shooting with my 13 year old granddaughter. Not having any AutoRim cartridges on hand, we went through a 50 round box of ACPs. She was impressed with the way a 1918 lifts instead of flips on firing. Still a great pistol/ammo combination if you want to get back on target quickly. Much quicker than with a 1911.

Unlicensed Bozo

I liked this article. Now do one on the 9mm please.


There is nothing elite about lapd. Corrupt top to bottom.


I don’t like the idea of firing a .44 round ball in a 1873 SAA (AKA “Peacemaker” and “Colt 45”), which uses 45 Long Colt cartridges.


I can’t figure if you are being knowingly facetious or unknowingly ignorant.


“While the old cap-and-ball 1860 Colt Army and 1873 Single Action Army used a .44” round ball, and a 255gr .454” flat-tipped conical lead bullet, respectively,”

Seems correct to me.

Clark Kent

‘Corrupt from top to bottom’? Proof of this claim? I will be waiting for verifiable FACTS, not hyperbole.


wnb must be spending too much time in th hood


Not to worry, he won’t have any proof other than his big mouth. He’s probably one of those guys that just paint everything with a wide brush. Oh, there is one exception. When he’s in big trouble, and LAPD shows up to assist, then their the great guy’s who saved his pigs ass bacon!