Chapter One: A Cartridge Is Born

It’s 1872. The Civil War is over, Reconstruction is underway, and the U.S. Army is getting tired of percussion revolvers and paper cartridges. The old cap-and-ball Colts like the Model 1860—while noble in their own way—are slow to reload, susceptible to fouling, and a bit too old-fashioned for the new breed of soldier galloping across the Western plains.

Enter Colt’s Patent Fire Arms Manufacturing Company, with a new revolver chambered for a brand-new metallic cartridge. The Army wanted something robust. Powerful. Simple to reload from the saddle. So Colt teamed up with the Union Metallic Cartridge Company (UMC) to design the round that would bring it all together: a centerfire cartridge launching a big ol’ lead bullet at enough velocity to stop a horse, a bandit, or—if the stories are true—a charging grizzly.

The result was the .45 Colt, a rimmed, straight-walled cartridge with a 255-grain bullet and roughly 40 grains of black powder tucked behind it. It was as American as barbed wire and beef jerky.

Chapter Two: The Gun That Made It Famous

Image: Restored Colt Single Action Army Revolver from 1884. Explore our gallery to see additional restored Old West firearm examples.

The Colt Single Action Army revolver, introduced in 1873, became the .45 Colt’s first—and most famous—dance partner. With its 7½-inch barrel, solid frame, and smooth-triggered action, the SAA quickly became the Army’s official sidearm and the archetype of the Western revolver.

Now, let’s pause here. There are few duos in firearms history as inseparable as the Colt SAA and the .45 Colt. Like bacon and eggs. Or Wyatt Earp and Tombstone. The gun and the cartridge were designed for each other from the start, and the U.S. Army took note.

The official pairing was adopted as the Model 1873, and soldiers began receiving them soon after. These six-shooters (usually cavalry models with longer barrels) became standard issue during the Indian Wars and saw action across the ever-expanding western territories. They were rugged, powerful, and relatively easy to reload in a pinch. A trooper could carry extra cartridges in a belt or pouch and forget about paper cartridges or percussion caps once and for all.

And let’s not forget: this was a man-stopper. The .45 Colt’s heavy lead bullet didn’t need high velocity—it hit like a freight train.

Chapter Three: The .45 Schofield Affair

No story of the .45 Colt is complete without mentioning the .45 Schofield, a slightly shorter cartridge adopted by the U.S. Army not long after the Colt SAA. Smith & Wesson had introduced the Model 3 Schofield revolver in 1875. The Schofield variant of the Model 3 was a top-break design favored by some cavalry units for its faster reloads.

The Schofield cartridge was similar to the .45 Colt but used a shorter case and slightly lighter powder charge. It would chamber and fire in a Colt, but the longer .45 Colt wouldn’t fit in the Schofield’s cylinder.

This led to a logistical nightmare. The Army couldn’t issue both cartridges and expect smooth supply chains. In the 1870s, you couldn’t just call up Logistics Command and reroute a shipment from Fort Riley to Fort Apache. So, the Army standardized on the shorter Schofield cartridge, M1887 Military Ball Cartridge, which worked in both guns.

To distinguish the longer round from the Army-issued version, civilians and dealers began referring to it as the .45 Long Colt—a nickname that still hangs around today, though technically there’s no official “.45 Short Colt.”

But if you ever want to see a gun forum turn into a theology debate, just bring that up.

Chapter Four: From Frontier Justice to Fading Fame

Image: .45 ACP rounds. Designed by John Moses Browning in 1905, and eventually adopted by the United States Military with the Model 1911. Read more about the history and legacy of .45 ACP.

Through the 1870s and 1880s, the .45 Colt rode shotgun (sometimes literally) in the holsters of lawmen, outlaws, ranchers, and soldiers alike. You’ll find it in the stories of Bat Masterson, Bill Tilghman, and a dozen other frontier figures—though many switched guns and calibers over the years. Still, the .45 Colt earned its reputation the hard way.

As the 19th century drew to a close, though, the .45 Colt started to lose ground. The U.S. military began transitioning to double-action revolvers chambered in smaller calibers—first the .38 Long Colt, then eventually the .45 ACP with the adoption of Browning’s Model 1911.

By 1892, the Single Action Army faded into obsolescence in military circles, and so did the cartridge it carried. Colt even ceased production of the Peacemaker for a time, shifting toward double-action designs and newer cartridges.

But just when you thought it was headed for the history books, the .45 Colt made one heck of a comeback.

Chapter Five: Hollywood and the Cowboy Revival

Image: .45 ACP rounds. Designed by John Moses Browning in 1905, and eventually adopted by the United States Military with the Model 1911. Read more about the history and legacy of .45 ACP.

In the 1950s, America rediscovered the romance of the Wild West.

Television and movies beamed tales of frontier heroes into every living room—Gunsmoke, Bonanza, The Lone Ranger, and countless John Wayne films rekindled our national love affair with lever-actions, stagecoaches, and six-shooters.

Colt responded with the Second Generation Single Action Army revolvers, reintroduced in 1956, once again chambered in .45 Colt. Ruger joined the party too, offering robust single-actions (like the Blackhawk) that handled hotter loads, using modern steels and designs.

The result? A full-blown renaissance for the .45 Colt.

Collectors, cowboy action shooters, re-enactors, and good old-fashioned gun cranks embraced the cartridge once again. Ammo companies brought out new factory loads, and handloaders found that the big case offered endless room for experimentation.

Chapter Six: Cowboy Action and the Modern Legacy

Image: Factory-new Uberti SAA, featuring restoration-grade finishes by Turnbull. Explore our gallery to see additional custom finishes for new firearms.

Today, the .45 Colt is one of the most cherished cartridges among Cowboy Action Shooting competitors. Light loads with soft-lead bullets and fast-burning powders are the norm. It’s about speed, nostalgia, and the joy of ringing steel with six-guns and lever rifles.

Some shooters prefer lighter calibers like the .38 Special for reduced recoil and faster times. But for those who like to shoot with a bit more boom—and with an eye toward authenticity—the .45 Colt is still king.

Modern revolvers chambered for the .45 Colt are also favored in trail defense roles by backcountry hikers and hunters. You’ll even find the .45 Colt in combo guns like the Taurus Judge and Smith & Wesson Governor, which can chamber .45 Colt and .410 shotgun shells. While those guns are niche tools, they’ve introduced the cartridge to a new generation of shooters.

Final Chapter: Why It Still Matters

The .45 Colt isn’t just a cartridge—it’s a living piece of American history.

It was there when the frontier was still wild and woolly. It rode with cavalrymen chasing Geronimo, with Texas Rangers holding the line, and with settlers heading into the unknown. It fell out of fashion, then roared back thanks to Hollywood, hobbyists, and hunters.

Collectors of classic Colts know: no revolver collection is complete without at least one Single Action Army in .45 Colt. Students of military history recognize it as the cartridge that helped the Army modernize after the American Civil War. Lovers of Western lore hear the clang of saloon doors and the creak of saddle leather every time they drop a .45 Colt cartridge into a loading gate.

And as long as there are cowboys at heart, campfire storytellers, or folks who love the ring of a steel plate at 25 yards, the .45 Colt will keep doing what it’s done for over 150 years—deliver power, pride, and a little bit of magic.

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