Lots of shooters, of all walks, prefer a pistol chambered in .45 ACP. It’s a powerful round that makes a big hole and is very reliable, both to feed and fire. But the cartridge is getting up there in age, and though the gun it was designed for, John Browning’s M1911, is still a relevant handgun, the .45 ACP is 111 years itself old and could use some updating.
This article from Guns.com does a great job explaining the shortcomings of the round, which were advantages when it was designed. The .45 ACP was created in a time of trench warfare, when things needed to function at a moment’s notice and do so reliably in harsh, dirty conditions. The round is forgiving, and it was also made to allow for bullet setback from hard handling before use.
Much of the case of a .45 cartridge is empty, so if a bullet is shoved back into the casing, it’s not really a problem. With a round that contains a lot of propellant, a bullet being pushed into the case can compress the powder and cause a spike and catastrophic failure.
Modern ammunition manufacturing makes bullet setback far less of a problem, thereby nullifying the advantage of a roomy case. Two newer cartridges, the .45 Super and .45 SMC, take advantage of that space with thicker brass walls and a higher charge.
For example, in a recent test, standard-pressure .45 ACP ball ammo came in at 300 to 350 foot-pounds of force at the muzzle, about the same as many 9mm Luger loads, and a little softer than most .40 S&W loads. Self defense +P hollow-points scored between the 400 and 525 foot-pound range. For .45 Super and .45 SMC, 500 foot-pounds is entry-level. Most loads offer muzzle energies in the 600 to 650 range with Double Tap’s 185-grain SMC kicking with 749 foot-pounds of force in a full sized Glock 21.
To read more about how the ballistics of the new rounds compare with the standard .45 ACP, go here.