.45 Colt Ammo

45 Colt Summary

.45 Colt: In Depth

In the years immediately following the American Civil War, self-contained metallic cartridges were just starting to break through into the mainstream. After using cap and ball revolvers for many years – and then converting many of these same guns to metallic cartridge firing later – the US Army decided they wanted a purpose-built cartridge revolver. After testing several options, they liked Colt’s Open Top best. However, they didn’t think the .44 caliber cartridge it shot was big enough, nor did they appreciate the Open Top’s…open top. They wanted a revolver with a top strap – a frame component above the cylinder that connected the two halves of the gun. They believed this feature would make the revolver much stronger and far more durable in the hands of any careless troops. By the time Colt reworked the Open Top to the Army’s satisfaction, they had produced both a new gun and a new cartridge.

The gun we know as the Colt Single Action Army, and the cartridge, .45 Colt. The Army was firmly committed to all things .45 caliber at the time (1873), having also adopted the .45-70 rifle cartridge to go along with the Springfield 1873 Trapdoor rifles and carbines, and having approved the Smith and Wesson Model 3 revolver with its .45 Schofield ammunition shortly thereafter. As it turned out, the .45 Colt chambered Single Action Army could shoot the .45 Schofield round, but the Model 3 chambered in .45 Colt couldn't do the reverse. For a time, the Army even chose to issue the Schofield round in far greater numbers, in order to ease ordnance logistics. After a few years, however, .45 Colt was by far the dominant revolver cartridge between the two. 

Unfortunately, the small rim of the .45 Colt prevented its use in lever action rifles due to unreliable case extraction. The massively successful Winchester 1873 rifle and .44-40 cartridge, on the other hand, made a fantastic team. It’s possible that this lack of a companion carbine or rifle for the SAA diminished its popularity for the average rancher or cowboy of the era.

In June of 1876, it was carried into the infamous Battle of the Little Bighorn for use in Colt’s Single Action Army revolvers. Though the encounter was a resounding defeat for General Custer and his cavalry troops that day, it certainly wasn’t trouble with the pistol that doomed the men, but rather a combination of other factors, including known extraction issues with the .45-70 Springfield carbine. In any event, Little Bighorn is one of many threads that wove .45 Colt into the tapestry of Old West lore; nostalgia for this time period would drive the popularity of the cartridge sky high in spite of its abandonment by the Army just a few years into the 1890s. 

For, even though it proved to be a more than ample “man stopper” when tested in combat, in 1892 the cartridge was snubbed by the Army in favor of the .38 Long Colt and M1892 revolver. This new revolver, despite its smaller caliber, had a swing-out cylinder and double-action capability – outclassing the older SAA. Worldwide events would steer the military back to .45 caliber soon enough, however, as .45 ACP would become the official sidearm cartridge for most branches by 1911. 

Long after the military had moved on to semi automatic pistols, the US population at large continued to be die-hard revolver fans. Many owned surplus Single Action Army revolvers and some even used them to hunt. Renowned handgun hunter Elmer Keith famously blew one up using .45-70 bullets and a full case of black powder during one of his many load development escapades, leading him to focus on different revolvers and cartridges after the incident. It was agreed, even in the 1920s, that revolvers chambered in .45 Colt were not a good platform for high pressure loads. Ruger was able to address this decades later, beginning with their release of the tanklike New Model Blackhawk and later Redhawk revolvers. The giant case capacity of .45 Colt also helped things, leading it to become a popular option for hunting, and defense against dangerous game.

In the 80s and 90s, the advent of Cowboy Action Shooting and the release of the first lever guns chambered in .45 Colt both helped rekindle interest in the Old West holdover. Somewhere along the way, .45 Colt brass got an extractor groove cut above the rim, enabling it to feed reliably through lever actions. At long last, the old SAA got its companion rifle! 

The .45 Colt’s long run is partly due to nostalgia, certainly. But the big old fat cases and giant bullets that go on top of them can stomp butts bigtime in the meanest loads. There’s a little something for everyone here, regardless of your chosen sport. 

.45 Colt: Guns

Firearms in .45 Colt are either revolvers or lever-action rifles for the most part, though there are some single-shot rifles as well. Ruger in particular is known for their stout revolver actions – they should be the number one choice if you’re planning to use .45 Colt +P ammunition in your handgun. Taurus’ Judge and S&W’s Governor shoot both .45 Colt and .410 Shotshells (along w/ .45 ACP for the Governor), and there are also a ton of replica Single-Action Army pistols from Cimarron and Uberti – these are the guns you shouldn’t run +P ammo in! Any .45 Colt gun is also capable of shooting black powder loads, should you choose to do so: just remember to clean your firearm thoroughly and often if you run BP.


  • Colt Single Action Army
  • Ruger New Model Blackhawk
  • Taurus Judge
  • Ruger Redhawk
  • Smith and Wesson Governor
  • Cimarron Cavalry Scout 

Lever-Action Rifles

  • Winchester 1892
  • Henry Big Boy Brass Deluxe
  • Rossi R92
  • Winchester 1873 Deluxe Sporting

Why Choose .45 Colt?

This is a round that seems to have at least two very different audiences: the CAS crowd and plinkers, and those in need of big-bore magnum performance. Using special factory loads, or by downloading powder in handloads, cowboy action shooters are able to get bullets that barely squeak past the muzzle in replica SAAs and vintage guns. On the other hand, with the right frame strength, incredible pressures can be achieved safely with this cartridge. Ruger’s New Model Blackhawk and later Redhawk revolvers are both built with sufficient beef to handle .45 Colt +P ammunition, which either approaches or exceeds .44 Magnum pressures, depending on the load! Many folks handload .45 Colt to extreme pressures or use one of the dozens of factory loads in appropriate revolvers for defense against dangerous game or to hunt large critters.

Target / Competition

  • Huge market for replica SAA (Colt Single Action Army) guns and target loads to run in them makes it easy to go plinking.
  • Cowboy Action Shooting competitions make heavy use of this cartridge.
  • Cowboy loads won’t damage older or replica revolvers.


  • Hunting loads are available with heavier (265-gr. and up) bullets going in excess of 1,500/fps.
  • Biggest bullets above 300-gr. usually found in dangerous game loads.

.45 Colt: Ammo Brands and Loadings

In addition to the standard pressure ammo and replica-safe loads made by the biggest manufacturers, +P options from Underwood and Buffalo Bore are available; both of those manufacturers produce stout options for backcountry defense and hunting applications. As previously mentioned, don’t shoot .45 Colt +P in anything but the strongest actions – typically one of the Rugers –  and verify that your particular model is up to the task beforehand. The firearm and/or ammo manufacturer should be able to give you some advice here on your particular model. Ammo labeled “Cowboy Action” will be safe in any revolver (even an old one), provided the gun is in good condition. Black powder loads are also out there, but not as common. 


Standard Loading

  • 250-gr. FN @ 750/fps to 850/fps

Bullet Types

    • FN (Flat Nose) - Target, self defense, hunting
    • WC / SWC (Wadcutter / Semi-wadcutter) - Hunting, target
    • HP / JHP (Hollowpoint / Jacketed Hollowpoint) - Self defense, hunting
    • Fluted / Penetrator - Hunting, self defense
  • Shotshell - Pest control 

Bullet Weights

  • All over the place! Anywhere from 125-gr. to 335-gr. and higher!


  • 700/fps to 800/fps - Cowboy action and lighter loads  
  • 850/fps to 900/fps - “Standard” velocity target and some hunting loads
  • 1,000/fps to 1,500/fps - Hunting and critter defense loads

+P Ammunition / “Ruger Only” Loads

  • High pressure +P ammunition is available for hunting and bear defense.
  • This ammo should not be run in older firearms or new-production SAA replica firearms.
  • Also referred to as “Ruger-only” loads since the Ruger New Model Blackhawk and Redhawk were initially some of the only revolvers that could consistently handle the ammo.
  • Safe to shoot in lever-action rifles.

.45 Colt: Frequently Asked Questions:

Yep. If you see a reference to “.45 Long Colt” somewhere, they’re talking about .45 Colt.

The thing is, most people agree that “.45 Long Colt” has never been a production cartridge! It’s just another name for .45 Colt that some folks used in the past. 

They are two completely different cartridges!

.45 Colt is a rimmed revolver round, whereas .45 ACP is rimless and intended for semi-auto pistols.

They don’t chamber in the same firearms (except for some revolvers that are able to shoot .45 ACP with special “moon clips”, or modified cylinders).

Ruger New Model Blackhawks and Redhawks are strong enough to handle this ammunition.

You should not use +P ammo in S&W Governor and Taurus Judge revolvers, older revolvers, and replica revolvers.

Rifles are good to go for +P.

Absolutely. Especially with +P ammunition, .45 Colt is able to deliver a ton of power through the right firearm.  Since this is a handgun round, max hunting range is about 50 yds.

While there are better (as in lighter weight and higher capacity) firearms for home defense, a big steel revolver with six .45 caliber rounds will certainly work!

Taurus’ Judge and S&W’s Governor revolvers both target the home defense market. While they are versatile in the sense that they chamber several different cartridges, they are no more effective than other revolvers for shooting .45 Colt. A Uberti or Cimarron SAA replica will work just fine!