45 ACP Ammo

.45 ACP Overview

.45 ACP Ammo: In Depth

Most modern-production pistols can trace their distant forebears back to a particularly ferocious era of firearms development circa 1900. Starting from this point, smokeless, rimless ammunition designed for auto-loading pistols would be the new standard to feed the sidearms of the world’s militaries. Spearheading this charge into smokeless autoloaders was a man who was celebrated by his peers even then. A man who has, without a doubt, been revered by firearms enthusiasts ever since: John Moses Browning.

Browning’s early pistol designs for Fabrique Nationale, known as the Models 1899 and 1900, chambered a smokeless, straight walled, semi-rimmed cartridge of his own design – 7.65x17mm Browning (here in the US, it’s called .32 ACP - Automatic Colt Pistol) – and featured the first reciprocating slides on blowback actions. His concurrent designs for Colt’s Manufacturing Company introduced the short-recoil operation system, first seen on the Colt Model 1900 and continuing with several variants over the next three years (all chambered in .38 ACP, which he also designed). Though the US military would briefly test the Colt M1900 as soon as it was available, it was not adopted; nor was its successor – the Model 1905.

However, the Model 1905 carried at least one crucially important distinction compared to its predecessors: it was chambered for yet another new cartridge designed by Browning: .45 ACP. It featured a bullet that was a good deal larger than anything seriously deployed in an autoloader up to that point; possibly in reaction to a brutal test commissioned by the Army in 1904, or perhaps more generally to the notion that .38 Long Colt (standard-issue US sidearm cartridge of the time) and its peers-in-caliber didn’t carry enough energy into an attacking assailant. This is the era that birthed the infamous idea of “stopping power”: an idea that would hang heavily over handgun theory and practice in the US military for the next eighty years.

Following the Army handgun trials conducted in 1907, further improvements were made by Browning and Colt over the next four years, finally culminating in the Colt Model of 1911, one of the most distinguished firearms in history. By that time, the standard .45 ACP load sported a 230-gr. FMJ bullet traveling at 850/fps, a combination which was quite powerful for the day. In addition, the pistol’s magazine held seven rounds vs. a revolver’s six.

Within a few years of adopting the M1911, the US military found itself shipping many thousands of them to Europe to arm American troops in WWI. Notably, however, existing stocks of the autoloading pistols were low before the conflict began, so both Smith and Wesson and Colt also produced revolvers chambered in .45 ACP that made their way overseas, albeit with the addition of “moon clips”, which enabled the rimless cartridge to operate in a revolver platform. These M1917 revolvers, as they were called, would continue to see action in WWII and beyond.

In the aftermath of WWI in the US, the military, FBI, and criminal underworld all quickly recognized the effectiveness of the new Thompson submachine gun's fully-automatic .45 ACP fire. Particularly with its front foregrip and drum magazine installed, this gun is a potent symbol of the Prohibition and gangster era in the United States that endures to this day. 

The .45 ACP cartridge further cemented its reputation in combat during the next world war in Europe, North Africa, and across the Pacific. Both the M1911 and the later M1911A1 variant saw extensive action in WWII, earning the trust of GIs and the respect of enemy combatants alike. The iconic Thompson submachine gun, now configured as the M1 or M1A1 and carrying twenty or thirty rounds of .45 ACP in its box magazines, saw military service in these years as well. A far less costly .45 ACP submachine gun, known to troops as the “grease gun”, was made from stamped metal parts and made its first appearance later in the war. The M3A1 Grease Gun would also serve in Korea. M1911 pistols continued to be used through the Vietnam War and throughout the 70s and early 80s.

What the military could not change, however, was that the .45 ACP was not an easy cartridge to master in a pistol; the round produced considerable recoil, even when paired with the heavy steel frame of the M1911A1. Partly due to this fact, and partly in reaction to considerable international pressure to standardize ammunition, the decision was made in the 1980s to move from .45 ACP to 9mm NATO. In 1985, the Beretta M9 pistol chambered in 9mm NATO became the official US military sidearm, with the exception of Marine Corps troops, who continued to field the M1911A1 for many years afterward.

Nevertheless, the US military’s shift to 9mm NATO did little to discourage the wider shooting public’s adoration of the M1911 and its .45 ACP ammunition. After all, this partnership served with distinction through two world wars in addition to countless other engagements, and many saw (and still see) the 1911 as the pinnacle of pistol design and elegance. There is a massive market for custom-built or otherwise high-end 1911s; some are routinely priced between five and ten times what a Glock 21 will fetch, for example. However, for the right person, this is a small price to pay in order to enjoy the fine craftsmanship inherent to many of these guns, and also to capture just a bit of the mystique and tradition that surrounds the legendary 1911.

.45 ACP: Guns

The 1911 and its close variants have dominated the .45 ACP firearm market since the very beginning of the cartridge. While it’s true that M1917 revolvers were produced in large numbers, submachine guns were used for decades, and newer polymer pistol designs helped to shed some weight for ease-of-carry, the good ol’ steel M1911 remains the true companion of the .45 ACP cartridge, and is almost single-handedly responsible for its enduring popularity. However, semi-automatic versions of the well-known submachine guns used in the 20s - 50s, especially the Thompson, are still manufactured, along with many historic and some post-86 NFA guns.


  • Colt Government 1911C
  • Springfield Armory 1911 Loaded
  • Smith and Wesson 1911TA E-Series
  • Kimber Super Match II
  • Wilson Combat Tactical Supergrade
  • Nighthawk Custom Talon

Later Designs and Polymer-Framed Pistols

  • Smith and Wesson M&P 45
  • Sig Sauer P220
  • HK 45 V1
  • FNX 45 Tactical

Revolvers (Will Require Moon Clips)

  • Smith and Wesson M1917 / Colt M1917
  • Smith and Wesson Model 325
  • Smith and Wesson Governor (.45 Colt, .410 Bore)
  • Charter Arms Pitbull

Submachine Guns

  • Auto-Ordnance Thompson M1
  • Kriss Vector SMG

Why Choose .45 ACP?

This cartridge is one of America’s all-time favorites: drenched in enchanting nostalgia and draped with marvelous military tradition. Beyond all that, it’s a real pounder of a round. From the very beginning of its history, perception and continued use of the .45 ACP has been influenced by the notion of “stopping power”.

Target / Competition

  • Long history of finely-tuned M1911s being used in competition goes back to the 1910s-20s.
  • Large selection of target pistols available including “custom shop” and off-the-shelf models.
  • While not as cheap to shoot as 9mm Luger, .45 ACP FMJ “ball” is made by most ammunition manufacturers.

Concealed Carry / Defensive Carry

  • For decades in the US, specifically carrying a 1911 “cocked and locked” (condition 1) was the only way many folks would even consider carrying a firearm. 
  • Lighter weight contemporary pistol designs have made carrying a .45 ACP firearm more feasible for some, though the ammunition is still quite heavy on its own. However, a full mag inside of a steel 1911 is too stout a package for many.
  • Bullet technology has leveled the playing field somewhat between 9mm Luger and .45 ACP in terms of terminal ballistics, so the advantages of .45 ACP are not what they once were. Nevertheless, it’s a hard hitting round that is extremely effective in a defensive situation.

Home Defense

  • .45 ACP is more than adequate for defensive situations in the home. It may be worth considering a smaller caliber, however, if the firearm operator is small statured, or otherwise would have a hard time controlling the recoil of this cartridge. The fact that 1911 pistols already weigh two or three lbs without ammo does help manage some of the snappiness.


  • As with many other pistol cartridges, you certainly could hunt with .45 ACP if pressed, but there are much better (and far more ethical) options: 10mm Auto, for instance.
  • Most loads feature FMJ or JHP projectiles and are designed for target shooting or defense against people rather than animals.

.45 ACP: Ammo Brands and Loadings

This cartridge is manufactured by just about any outfit that produces handgun ammo. 230-gr. FMJ loads are the most common, along with similar weight JHP loads. Its military service footprint is extremely small compared to when the M1911A1 was still standard issue, so surplus ammo is not easily found.


Standard Loading

  • 230-gr. FMJ @ 850/fps.

Bullet Types

  • FMJ (Full Metal Jacket) - Target, competition, aka “ball” ammo
  • JHP (Jacketed Hollow Point) - Self Defense
  • FN (Flat Nose) - Unjacketed hard-cast bullets for critter defense
  • Monolithic / Penetrator - Defense plus barrier penetration

Bullet Weights

  • 135-gr. - Penetrator
  • 175-gr. to 210-gr. - Self defense JHP
  • 230-gr. - Standard Weight FMJ and JHP
  • 255-gr. - Hard-cast lead


  • 135-gr. - 1,250/fps
  • 175-gr. to 210-gr. - 1,000/fps to 950/fps
  • 230-gr. - 850/fps
  • 255-gr. - 925/fps (+P)

+P Ammo

  • This indicates that a round has more chamber pressure. This is especially common in defensive loads with hollow-point bullets. Expect more recoil from these rounds, and avoid using them in antique firearms.

Non-Brass-Cased Ammo

  • Both aluminum and steel-cased ammunition is commonly available in .45 ACP.
  • With the rare exception of some older steel-cased ammo being corrosive (clean your pistol right away when you’re done shooting that stuff), this ammo is good to go. Aluminum cased ammo is totally fine.
  • Neither aluminum or steel-cased ammo is reloadable – at least nowhere near to the extent that brass is.

.45 ACP: Frequently Asked Questions:

.45 ACP is a rimless cartridge designed for a magazine-fed semi-auto pistol. .45 Colt and .45 Long Colt are terms used more or less interchangeably to refer to an earlier revolver cartridge that has little to do with .45 ACP.

45 Auto Rim is essentially .45 ACP with a rim, and was developed for use in M1917 revolvers, which required the use of “moon clips” to fire .45 ACP through their cylinders.

It definitely is, provided that you take the time to train and learn to manage the recoil. If the recoil is not a problem for you, it’s a superb choice. Some people will find a fully loaded all-steel 1911 too heavy to carry for long periods of time.

.45 ACP ammo is fat. This means the grip will be pretty thick if you want decent mag capacity. 1911s in traditional form use a single-stack mag, so this is not a problem, but you are still limited in total capacity compared to a cartridge like 9mm Luger.

Given the various performance boosts that defensive 9mm Luger +P ammo has received over the years, the decision to carry a bruiser like .45 ACP might not look quite as appealing.

Yes, though same as with defensive carry outside the home, recoil may be a bit more than you’d want in the middle of the night or under considerable stress. Training can help with recoil anticipation and/or throwing follow-up shots, as can moving to a lighter weight bullet.

Making an accurate and effective shot on game with a .45 ACP handgun at a distance beyond 10 yds or so is a challenge for most people. Hard-cast bullet loads that are heavy-for-caliber may be the best choice if you have no other, however, a 10mm Auto pistol is more effective and still semi-auto.