Too numerous cartridges wound up with comparable names regardless of being totally different native one another. We regularly have shooters ask us if they have the right to fire 38 super in your 38 distinct revolvers. It’s perfectly fair the them come wonder if they can – “super” and also “special” are comparable concepts, after ~ all, and it doesn’t help when they’re preceded by the exact same number.

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

“Why i will not ~ this ammo i ordered from friend fit in mine 1911?” We recognize the answer before they speak anything further: “You acquired the not correct ammo!”

The Difference between 45 long Colt vs. 45 ACP

45 long Colt

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The 45 long Colt was occurred in 1872 in partnership by Colt and also the Union Metallic Cartridge Company, i m sorry is currently a subsidiary the Remington. Originally a black color powder ring by necessity, the U.S. Army embraced 45 long Colt in 1873. It offered as the official handgun ring for your Colt solitary Action military revolver because that 14 years.

45 ACP

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man Browning developed the 45 ACP in 1904. At the moment the military wished to replace their revolvers with semi-automatics, yet naturally there is no sacrificing accuracy or strength in the process. As the Thompson-LaGarde exam of 1904 had determined .45 caliber to be the most efficient pistol cartridge, Browning retained that bullet.

Browning’s 1911 pistol stayed the key sidearm the the U.S. Army until its replacement by the Beretta M9 in 1985 and then the 9mm SIG Sauer P320 in 2017. The primary difference in between the 45 lengthy Colt and also 45 ACP is readily apparent: One is designed for a revolver, if the various other is designed because that a semi-auto. The 45 lengthy Colt’s covering casing thus attributes a rim that allows it to sit securely in a cylinder.

While lot of of semi-autos can handle rimmed cartridges – the 22 LR being the most famous that pertains to mind – rims space generally thought about a detriment to smooth feeding and also extraction. If 45 ACP ammo technically does have actually a rim, its pickled in salt diameter is eight times smaller sized than the of the 45 long Colt’s when you compare the rim’s protrusion come the basic diameter of the cartridge.

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

The Similarities between 45 long Colt and also 45 ACP


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


John Browning didn’t set out to produce an entirely different cartridge 보다 that i m sorry the U.S. Military had come to be accustomed to. He actually developed the 45 ACP to match the ballistics that the 45 long Colt fairly closely! It’s no an apples come apples comparison, though. A common 45 lengthy Colt cartridge has actually a 250 serial bullet and also 860 fps muzzle velocity, offering it 411 ft lbs muzzle energy.

In comparison, a conventional 45 ACP cartridge has actually a 230 grain bullet and also 850 fps muzzle velocity, giving it 369 ft lbs muzzle energy. The 45 lengthy Colt is effectively a much more powerful cartridge, but with a 1911 you get seven shots in the magazine instead of 6 in the cylinder. That a lot easier to reload a semi-auto than a revolver once you’re in a hurry, too, i beg your pardon is why lock generally more favored. The 45 lengthy Colt has actually a .452” bullet.

The 45 ACP, ~ above the various other hand, has a .451” bullet. If you think about one one-thousandth the an customs a good length, then you may argue the the 2 cartridges’ bullets room in fact an extremely different from one another. It’s going to it is in a difficult sell, though.

See more: What Are The Three (3) Main Parts Of A Handgun? Basic Parts Of A Handgun

The Takeaway

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it’s dangerous come mistake part rounds because that others as soon as they share identical dimensions yet create an extremely different room pressures. That’s why you must take every precaution versus running 5.56×45 through a rifle chambered only for 223 Rem, and also why you additionally don’t desire to operation 9mm +P+ v an original Luger pistol.

Fortunately, she not most likely to wrong a rimmed 45 lengthy Colt for a rimless 45 ACP. They simply look too dissimilar to permit such a mix-up. Merely avoid to buy 45 ACP because that your solitary Action Army, or 45 long Colt for her semi-auto, and you’ll be safe. The only challenging task staying will be in reality hitting her target!