Too many cartridges wound up with comparable names regardless of being totally different from one another. We regularly have shooters ask us if they have the right to fire 38 super in your 38 distinct revolvers. It’s perfect fair the them to wonder if they might – “super” and also “special” are comparable concepts, after all, and also it doesn’t assist when they’re came before by the very same number.

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On the upper and lower reversal side, too countless cartridges additionally have multiple, dissimilar sound names. We obtain plenty of civilization asking if they deserve to fire 9mm in a Glock 17 through “9×19” engraved ~ above its barrel. Perhaps no 2 rounds’ names lead to an ext confusion 보다 the 45 lengthy Colt vs. 45 automatic Colt Pistol (ACP). Us dread gaining the phone call call:

“Why won’t this ammo ns ordered from friend fit in my 1911?” We know the answer prior to they to speak anything further: “You acquired the wrong ammo!”

The Difference in between 45 long Colt vs. 45 ACP

45 long Colt

The 45 long Colt was developed in 1872 in partnership by Colt and also the Union Metallic Cartridge Company, which is now a subsidiary the Remington. Initially a black color powder round by necessity, the U.S. Army adopted 45 long Colt in 1873. It offered as the official handgun round for their Colt single Action military revolver for 14 years.

45 ACP

man Browning arisen the 45 ACP in 1904. At the time the military wished to replace their revolvers through semi-automatics, however naturally there is no sacrificing accuracy or strength in the process. Together the Thompson-LaGarde exam of 1904 had figured out .45 caliber to it is in the most efficient pistol cartridge, Browning maintained that bullet.

Browning’s 1911 pistol continued to be the key sidearm of the U.S. Army until its instead of by the Beretta M9 in 1985 and also then the 9mm SIG Sauer P320 in 2017. The major difference between the 45 long Colt and 45 ACP is easily apparent: One is designed because that a revolver, if the various other is designed because that a semi-auto. The 45 long Colt’s shell casing thus attributes a pickled in salt that allows it to sit securely in a cylinder.

While plenty of semi-autos have the right to handle rimmed cartridges – the 22 LR being the most well-known that pertains to mind – rims room generally considered a hinderance to smooth feeding and also extraction. If 45 ACP ammo technically does have actually a rim, its in salt diameter is eight times smaller sized than the of the 45 long Colt’s once you to compare the rim’s protrusion come the basic diameter of the cartridge.

As a committed semi-auto cartridge, the 45 ACP features an extractor groove that offers a surface ar for a handgun’s extractor come purchase against during extraction. You will certainly not uncover such a groove top top a revolver cartridge. If you would certainly rather identify the 2 cartridges by their lengths alone, the 45 lengthy Colt is 0.325” longer.

The Similarities between 45 long Colt and also 45 ACP


A close-up shooting of 45 long Colt ammo on the left and 45 ACP ammo top top the right.

John Browning didn’t collection out to develop an entirely various cartridge than that i beg your pardon the U.S. Army had come to be accustomed to. That actually emerged the 45 ACP to complement the ballistics the the 45 long Colt reasonably closely! It’s not an apples to apples comparison, though. A typical 45 lengthy Colt cartridge has actually a 250 serial bullet and 860 fps muzzle velocity, providing it 411 ft lbs muzzle energy.

In comparison, a conventional 45 ACP cartridge has a 230 serial bullet and also 850 fps muzzle velocity, offering it 369 ft lbs muzzle energy. The 45 long Colt is effectively a much more powerful cartridge, but with a 1911 you acquire seven shots in the magazine rather of 6 in the cylinder. That a lot simpler to reload a semi-auto 보다 a revolver as soon as you’re in a hurry, too, which is why lock generally an ext favored. The 45 lengthy Colt has actually a .452” bullet.

The 45 ACP, on the various other hand, has actually a .451” bullet. If you take into consideration one one-thousandth that an inch a good length, then you may argue that the 2 cartridges’ bullets are in fact an extremely different from one another. It’s going to it is in a difficult sell, though.

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The Takeaway

it’s dangerous come mistake some rounds for others once they share identical dimensions however create an extremely different chamber pressures. That’s why you must take every precaution versus running 5.56×45 v a rifle chambered just for 223 Rem, and why you also don’t want to operation 9mm +P+ through an initial Luger pistol.

Fortunately, you’re not most likely to mistake a rimmed 45 lengthy Colt for a rimless 45 ACP. They merely look too dissimilar to allow such a mix-up. Merely avoid to buy 45 ACP because that your solitary Action Army, or 45 lengthy Colt for her semi-auto, and you’ll it is in safe. The only an overwhelming task continuing to be will be in reality hitting her target!