The 45 ACP was designed by John Moses Browning as a new cartridge for his new Colt Automatic Pistol, in 1904, destine to become the famed 1911. For those who have never heard of John Moses Browning, you should spend some time to get to know this famed gun inventor. His designs formed the basis of many of the firearms we love and cherish to this day. Perhaps the most well known, but under appreciated design is the tilt barrel design which dominates the pistol market today.
In terms of what is the most effective caliber today, the 9mm, the 40S&W or the 45 ACP, the answer is more or less settled for now. The 9x19mm is the preferred cartridge for military and law enforcement agencies world wide. The 45 has largely fallen out of favor for reasons we will discuss. However from it’s inception to well into the 1980’s and 90’s it dominated in a large potion of the pistol market.
This cartridge happens to be one of my favorite cartridges. For me, I do not get bogged down which cartridge is better. At the end of the day, pretty much every conventional pistol cartridge in use by military and law enforcement generate similar muzzle energies, and have similar terminal ballistics. So it makes sense to me to carry the pistol that holds more rounds. With that said, there are characteristics with how a 45 handles and shoots that I find enjoyable. Different from a 9mm and a 40 S&W, and hard to describe with words, but I’ll try.
Cartridge History
Before you set out developing a new cartridge you need to have a perceived need for that cartridge. What gap is the cartridge meant to fill? What will this cartridge do that others cannot? In today’s world it seems that we are introduced to new cartridges every year, many are geared towards maximizing some measure of performance from the AR-15 platform. Back in the 1900’s firearms were still a fairly new technology, one that was in it’s adolescence, and experiencing growing pains.
Up to the point of the late 1800’s firearm design was making progress but it was slow going. Black powder, which had been around for centuries, was a difficult propellent to improve on. Rifling would quickly become clogged with fouling, accuracy would suffer, velocity was limited, in addition the white smoke was a dead give away to a shooters location. Making a firearm was a labor intensive process that was slow and expensive. Parts had to be hand fitted, and the precision what limited by the machine operators of the day.
This all began to change with the industrial revolution. New, more intricate designs, became possible to manufacture economically, including manufacturing of parts to a precision and repeatability that had not been previously possible. There was also a new propellent on the market, one that was destine to replace Black Powder, a product that had been around for centuries. The limitations of black powder were largely overcome with the introduction of nitrocellulose and nitroglycerin.
These two developments, the introduction of smokeless powder, and the industrial revolution allowed firearms to be taken from an adolescent technology into maturity. It is surprising that so many cartridges held in high regard today, were developed during this transitionary period in firearms tech. The 45 ACP, 30-06, 9x19mm, and the 50BMG are a few examples. These cartridges are over 100 years old but they are still seen all over the battlefield today. What other technology has remained relatively unchanged but still considered as relevant today as when it was first introduced over 100 years ago?
The history of the 45 ACP goes back to the 45 Colt which was (still is) a black powder cartridge that was introduced a long side the Colt Single Action Army revolver. This pistol was adopted as the standard side arm for the US Military as a result of the pistol trials in 1872 and served as the standard side arm until 1892. During this time the 45 Colt developed a reputation for being a “Man Stopper” despite the relatively low velocity and heavy lead bullet.
In 1892 the Army switched from the Colt Single Action Army in 45 Colt to the Colt M1892, which was chambered in the 38 Long Colt. One of the main features that the 1892 offered was a double action trigger. However the 38 Long Colt did not carry forward the reputation of “Man Stopper” as the 45 Colt had earned.
If you ever wondered where the contention between 9mm and 45 calibers began, I suspect this was it’s origin. The 38 Long Colt fired a .358 caliber bullet weighing 150 grains at 750fps for a muzzle energy of 187ftlbs. The 45 Colt fired a .454 caliber 250gr bullet at 738fps for a muzzle energy of 302ftlbs. The frustration over the 38 Long Colt reach fever pitch in the after math of the Philippine–American War which ended in 1902. The US Army issued an emergency authorization allowing for the return to service of Colt Single Action Army revolvers.
The armies next service pistol was chambered in the 45 Colt in a revolver called Colt New Service, Model 1909. This was a double action revolver first introduced in 1898. When John Moses Browning sought to develop a new cartridge for his new service pistol in 1904, it is little doubt that the failures of the 38 Long Colt was fresh in his mind coupled with a military order that any new service arm “should not be less then .45 in Caliber.”
Eventually John Moses Browning’s pistol won the service pistol trials and in 1911 was adopted as Model 1911, or M1911. This cartridge was the first pistol cartridge adopted by the United States Military that utilized Nitrocellulose instead of black powder. The original loading that passed testing was a 200gr bullet, fired at 900fps, however this would later be revised to a load that shot 230gr at 850fps. This new load developed 396ftlbs of energy at the muzzle. This loading exceeded the power of the original 45 Colt loads.
The 1911 and the 45 ACP went on to serve the US military as it’s standard side arm until the 1980’s when it was retired in favor of the Berretta M9 pistol chambered in 9x19mm. As people who promote the 45 ACP note, the 45 ACP is the longest serving side arm cartridge in the US military to date.
The reputation of the 45 ACP being a manstopper is no doubt a carry over from the 45 Long Colt. While it was, and still is an effective defense round, the larger case results in a lower magazine capacity. This is where the 9x19mm has has the edge, allowing for more rounds to be carried, as both rounds deliver a similar amount of energy to target. Reputations aside, the 9x19mm has been proven to be, as effective as the 45 ACP at stopping threats, and to date it has become the preferred cartridge for about 60% Militaries and LEO worldwide. Still the 45 has at least one big advantage over the 9mm Luger.
Most loadings in the 45 are subsonic, even with +P lighter bullets to about 160gr are considered subsonic when fired from a pistol. This makes suppressing the 45 ACP more effective then some of the alternative calibers. It’s inherent suppressibility, and the “Stopping powder” (real or perceived) of the 45 caliber were the reasons it was selected as the caliber of choice for the Offensive Handgun Weapon System as spec’d by United States Special Operations Command (SOCOM) in 1989.
This ultimately resulted in the development of the Heckler & Koch Mark 23, and then the future development of H&K’s USP series of pistols. The first units of the Mark 23 were delivered in 1996. (This large pistol requires big hands to use, but is an absolute blast to shoot.)
There have been several attempts to modernize the 45 ACP, cartridges such as the 45 Super, 45 Winchester Magnum, 45 GAP, and the 460 Rowland. While they have all been developed and released commercially, non have taken off to be anything more then intrinsic curiosities. Even as someone who is a fan of the 45 ACP, I recognize that it is a caliber that has slowly began to fall out of favor, and is likely to continue on a very slow descent into obscurity.
Technical & Load Information
45 ACP standards are published by both CIP and SAAMI. SAAMI Lists the service pressure of the standard load as being 21,000psi, while CIP list their Pmax pressure at 18,800psi (1300bar). CIP employs a stricter standard when it lists it’s service pressure (Pmax) as their standard states that no single shot shall exceed the Pmax, while the SAAMI states the average of Ten Shots shall not exceed service pressure. This means that manufacturers must load more conservatively in order to meet the CIP spec. Thus it is to be expected that 45 ACP ammunition produced in, or shipped to CIP countries will be less energetic then ammunition found on the shelf here in the United States.
In addition as far as I am aware, CIP does not recognize the +P designation. SAAMI Lists the Maximum Average Pressure of +P ammunition at 23,000psi. It is important to note that some companies will advertise at +P+ designation, this is not a SAAMI Standard, and if it exceeds 23,000psi, (as would be inferred by the +P+ designation) it is not considered safe to fire in firearms rated for the +P ammunition. Also not all pistols are rated to fire +P ammunition so you must know if your pistol is. I suspect the confusion around +P is one of the reasons why SAAMI will not likely approve any future +P designations for cartridges.
The service pressure for the 45 ACP is quite low, even when compared to it’s European counterpart 9x19mm. Initially the low pressure was desirable as it promoted a long service life, however as metallurgy and designs improved, the 9mm Luger chambered pistols have a comparable service life to the original 1911 pistols.
Loading for the 45 ACP is quite easy. It does excellent with cast bullets, I have not had a problem loading cast bullets for pistols with polygonal bores, despite the warnings, they do not seem to lead up any more then conventional bores. There is a large selection of bullets to choose from, and just as large of a selection of powders. I typically use Unique, or Bullseye for more of my target I.E “Plinking” loads. You do need to be careful doing this as you can easily fit two or three charges in a case, which would be a disaster.
I personally do not load to +P standards, if I want to practice with +P ammunition, I’ll purchase a new box of defensive ammunition, and shoot the old stuff. (It’s a good idea to cycle through your defensive ammunition at least every 6 months.) If you are looking to get top velocity, 45 ACP likes some of the slower powders used for pistols. Blue Dot, CFE Pistol, and Win 572 are good places to start.
As a general note the 45 ACP head spaces off the case mouth, thus a taper crimp should be used when loading for this round. Service life of brass is typically long, the brass is thin walled making it easy to size and the low pressures involved, coupled with the fact it’s a straight wall case means the case does not appreciably stretch.
SAAMI lists the max head diameter of a 45 ACP at .480in, comparable to that of the 308 Win at a diameter of.473in, thus some people with take 308 Win cases, shorten them and trim the necks make thick walled 45 Caliber cases capable of withstanding higher pressures. This is a common basis for many of the wildcat 45 cartridges.
Why Does it Make my List of Favorite Cartridges?
I’ve written a couple of these “Favorite” cartridge write ups, and I’m beginning to notice a bit a of a trend. I tend to like the old cartridges, especially if they are nearing obsolescence. Not sure what that says about me, after all I’m in my mid thirties, maybe I’m becoming old and obsolete and I just related to them.
No matter it still makes this list, because I enjoy shooting it. I will freely admit, that there is substantial data that shows the 9mm Luger is a superior cartridge. I credit the development of better bullet design for this improvement. If all we were doing was poking holes with full metal jacket bullets, then the 45 makes the larger hole, and thus causes more trauma. However that is not the case, as we have developed bullets that expand to greater diameters, retain a greater percentage of their weight, and do so more reliability then ever before.
Even though a 45 produces 25% more energy then the 9mm Luger, that not does mean more trauma is cause to tissue. The results of FBI testing, and numerous lab, and field testing has more or less show that the 45 ACP is as effective as pretty much any of the other standard defensive pistol calibers out there, including the 9mm Luger. Further more the smaller diameter of the bullet, combined with the high velocity allows it to penetrate deeper which increases the chances of injury to both skeleton and the central nervous system.
I have grown rather tired of the what is the “Best Caliber” arguments as they generally devolve into a screaming lecture devoid of data or reason. I am more of the “What do you shoot best” mantra. If you enjoy shooting a 357 Sig, and you shoot that better then other guns, then carry that. If you shoot a 45 ACP better then you shoot a 9mm Luger, then carry that. Often times the solution is not .100 greater diameter in lead, it is a few hundred rounds more in training. This point was even made by those critics of the 38 Long Colt, they felt that the round was under powered AND the troops were under trained. However it was easier for the army to increase bullet diameter then increase the training.
If it seems like I am arguing against the 45 ACP, it is because I am, a little bit. The reasons I enjoy shooting it, is not because I think it is a superior round in any way. Rather I enjoy shooting it because it is fun to shoot. I find that firearms chambered in 45 ACP tend to be a bit less snappy in recoil then other offerings. I would describe the recoil more as a slow push then snappy of lively. This is a subjective test, not an objective one, and why this caliber is my favorite, is hard to put hard data to justify it. Sometimes that’s the way favorite things work.