In this piece, we’re going to talk about one of the most popular full-size handgun cartridges of the last century, the 45 acp, or Automatic Colt Pistol – which is not the same as the confusingly similarly named .45 Colt. To kick things off, we’ll start off with a short history of the cartridges. From there, we’ll fill you in on the specifications of the cartridges that’s so well known for its stopping power in a wide selection of handguns. We’ll also go into some of the terminologies about the caliber, and compare the .45 to other rounds that are popular for concealed carry, such as 9mm.
No ammo is perfect, however, and we do want to make note of both the pros and the cons when we’re giving an in-depth background on this interesting caliber, so we’ll make the case that even though we enjoy shooting the 45 acp, it’s still one of the best calibers for all pistols or all shooter, but it’s still an excellent choice for full-size pistols.
Once we cover the cartridge itself, we’ll also make some comments on our personal favorites. Ultimately, we think that 45 acp into only has a lot of heritage in the past, but a bright future ahead of it as well.
History of the .45 Colt
The .45 Colt is often confused with the more common .45 ACP (also called .45 Auto) cartridge. While similar in some respects, they are not the same. The confusion often stems from the fact that ACP stands for “Automatic Colt Pistol”. The .45 colt is also called the “45 Long Colt” or can be shortened to “45 LC” to help differentiate it from other rounds.
The colt 45 cartridge is a somewhat older round: it was first developed in 1871 by Colt to meet a government need for a revolver that fired a self-contained cartridge. At the time, the development of a revolver for government use was an attempt to bring the army into the future.
Keep in mind the historical context here: in the not-so-distant civil war, most of the firearms in use by government forces were black powder firearms that were variations on a musket. By the end of the war, the revolver had been invented but was not yet in wide government service.
In the years after the civil war, the US government saw the need to replace single-shot sidearms for their soldiers and began to look into other options. At the time, many a county sheriff would have riled upon a revolver as a primary weapon: being able to use cartridges that come in a box, and be able to shoot them relatively quickly led to the quick introduction and adoption of revolvers, and the army began to pick up on that knowledge.
By 1873, the army had purchased both the .45 Long Colt round and the accompanying Colt Single Action Army Revolver (also called “Colt Peacemaker”). With these, the army replaced guns that fired a single round. These new Colt Model 1873 revolvers featured six rounds and operated in single action: you had to cock the hammer between each shot. Even though this is considered slow today, this Colt design not only solidified the company, and Colt’s own personal career, in the lexicon of history, but also introduced the world to the revolver, making the .45 Colt a major landmark in the slow transition from muskets to, by the 20th century, smokeless powder and semi-automatic firearms.
Place in History
Once the Colt 45 entered production, it became, in many ways, the major symbol of the government in the American West. Whether in the hands of a local sheriff or the army, revolvers firing this cartridge were used in the struggles for power (often on multiple sides) in the American West. This cartridge, fired in revolvers that had a lot of firepower for their weight, gave people heading out into the relative unknown a little more confidence.
The Colt Single Action Army revolver was used by multiple countries in many wars throughout history including the American Indian Wars, the Spanish-American War, and even WWI and a bit in WWII.
When Samuel Colt invented the round, he did a lot more than invent the 45 LC to meet government needs and further his career: he invented an object that would still be a part of the American conception of a historical period for years to come. It’s hard to say how many Colt 45’s were sold and supplied during this period, but we do know that even today, this page in American history is, in popular culture, defined by a cowboy with a hat on his head and a colt pistol on his hip. In this regard, the .45 Colt was the round that made the revolver popular, and cemented the historical place of Colt.
The .45 Colt is also sometimes called:
- .45 Long Colt
- .45 LC
Not to be confused with the similar 45 ACP (also called 45 auto).
45 Colt vs 45 Long Colt
The .45 Colt and the .45 Long Colt are just different names for the same round. There is no difference between them. The name is often used to differentiate it from the more recently developed 45 ACP.
.45 Colt vs .45 ACP Comparison
The first major difference between the 45 Colt and the 45ACP is the type of powder that they use. The Long Colt uses black powder. This means that when the round goes off, you can also expect a large cloud of smoke that will quickly obscure your vision. If you fire off all six from a revolver indoors, you’ll likely not be able to see much for a bit. The ACP cartridge fires smokeless powder, which is the substantially more modern powder. In addition to the lack of smoke, this also allows for higher pressures and velocities out of the same size projectile.
Revolvers generally don’t have a way to hold the cartridge in place before they are fired. Thus, the Colt 45 is a rimmed cartridge: there’s a brass rim that holds everything in place before the firing prin strikes the primer and detonates the round. These work awesome in revolvers but are generally awful in magazine-fed firearms.
The 45ACP is a rimless cartridge. This means that there is no, or very little, brass rim at the bottom of the cartridge. It would fall right out of a revolver designed like ones from the 1870s, but the lack of a rim means that these stack much better in a magazine like those used in the Colt 1911.
If we compare original loadings, the two cartridges are fairly distinct. The original .45 Colt also called 45 Long Colt, fired heavier projectiles that moved slower and with less energy owing to the black powder. By comparison, the original smokeless 45ACP fired a smaller bullet faster, resulting in flatter trajectories.
There’s a big caveat here, however: modern loadings of both of these cartridges, with smokeless powder, do perform comparably to each other.
|45 Long Colt||45 ACP|
|Case Type||Rimmed, Straight||Rimless, Straight|
|Bullet Diameter||.452 in (11.5 mm)||.450 in (11.4 mm)|
|Case Length||1.285 in (32.6 mm)||.898 in (22.8 mm)|
|Overall Length||1.6 in (40.6 mm)||1.275 in (32.4 mm)|
|Case Capacity||41.60 gr H2O (2.696 cm3)||26.7 gr H2O (1.73 cm3)|
|Max Pressure (CIP)||15,900 psi (110 MPa)||19,900 PSI (137 MPa)|
|Max Pressure (SAAMI)||14,000 psi (97 MPa)||21,000 PSI (140 MPa)|
Best .45 Long Colt Pistols
Colt Single Action Army Revolver
If you can find one, we highly recommend trying to pick up a historical, original, Colt Single Action Army. By modern standards, they’re not the best gun in the world: they’re heavy, not finished al that well, and have a mediocre trigger. With that in mind, it was a revolutionary firearm that changed not only firearms design, but also the landscape of the American West.
Assuming you can pick one up on shooting condition, have a gunsmith look it over and use only historically-correct loadings for these firearms.
Since their inception in 1872, Colt has stopped production of the Single Action Army several times from 1941-1956 and again from 1974-1976, but have been continuing producing them ever since. While modern versions don’t have the historical value of an original, they are a cool gun to own and shoot.
Heritage Rough Rider
While shooting the antiques is always fun, it is, if we’re being honest, a little disconcerting hoping something made in 1875 isn’t about to explode in your hand. Thus, picking up a modern take on the classics, such as the Heritage Rough Roider, is an excellent option.
These modern-made single-action revolvers shoot well and come with a safety meaning that you can be much safer when posing for pictures at the cowboy action shooting matches where these pistols are the most at home. If the Colt was our first revolver in this caliber, this one would be our second if we wanted to do some more shooting.
Cimarron New Sheriff
Most of the time, we’re not massive fans of new things made to look old, but we’ll make an exception here. Meant to look like an old gun with a brass frame that has some serious holster war, we think this single action revolver would not only make an excellent piece to display but would also be a seriously fun range toy. Also, part of us kind of wants to concealed carry it for the sake of historical nostalgia.
Uses For the .45 Colt
If you want to get into cowboy action shooting, or simply like the historical period, I can think of few better ways to refer to the aforementioned historical period than to slap a cowboy hat on your head and to get a 45 colt pistol, preferably either a Single Action or a good reenactment.
For this, you do have to be a little careful with ammo. While the 45 long Colt is an old cartridge, not all ammunition is the same. There are several good manufacturers that make historically correct loadings that are just fine to shoot out of a Colt Single Action. The random guy at the gun show, though, might well make cartridges that will fit in your old revolver but might well be loaded with modern powder that will cause massive damage.
A revolver in .45 Colt is one of the critical pieces to a historical reenactment of the old West, and thus if you’re into playing cowboy one way or another, we think that this one of the best ways to use Colt 45. With that said, we are distinctly glad we don’t have to use one of these revolvers in a last stand against a much larger force of extremely determined folks.
When compared to modern handgun and rifle cartridges, this old colt cartridge isn’t exactly the most powerful ammo deal that’s getting sent to your email inbox every day. With that in mind, for a period of several decades, it was a more than competent cartridge for self-defense and the kind of work that would often require using a firearm plenty of the time.
To be clear, we don’t think that we would choose a revolver in this caliber for home defense in 2022. But, if you had to defend yourself and no help was coming, then having a revolver in 45 colt would certainly be better than having to fight an intruder hand to hand when you could reach out and touch them with a blast from the past.
Additionally, the 45 colt is a more than capable cartridge if you plan to hunt small to medium game at short ranges. For instance, a lot of people fed themselves and their families with some combination of a lever-action rifle and Colt revolver, and we think that doing such a thing today is still more than possible if you have a passion for these kinds of historical cartridges and firearms.
Pros of the Colt 45
- The Colt 45 is the cartridge that you will need to shoot if you want to shoot antique firearms made for that caliber. It might be a little hard to find, and little bit expensive, but if you want to shoot older firearms more safely ,then tracking down the correct loadings and chamberings will help you keep your antique firearms in good shape for years to come. As far as reenacting or simply appreciating history goes, it’s hard to beat firing period-correct ammunition out of an antique cold Revolver: bonus points if you can do so in some of the more desert areas of the US.
- When you compare the felt recoil from, say, modern 9mm in a light concealed carry gun to an older Colt revolver chambered in 45 Long Colt, the 45 Colt feels substantially lighter recoiling even though it is shooting a much larger projectile. This makes it an exceptionally fun caliber to shoot: the large smoke clouds from black powder cartridges also add to the fun of shooting a fair bit.
Cons of the Colt 45
- Ammo is expensive these days no matter what caliber you’re shooting, and the problem generally gets worse as you get into more niche cartridges. This is certainly true of old, black powder, rimmed revolver cartridges. Thus, shooting the 45 Colt at any volume will likely come with a substantial expense. If you plan to do a lot of shooting in this caliber, we’d very much recommend getting into reloading so that you can make more of them when you need to at fairly substantial savings.
- Second, the 45 Colt is, in simple terms, an antique. When it comes to overall velocity and ballistic performance, it pales in comparison to 9mm, and even other somewhat old cartridges like the .45ACP to which it is often compared. Yes, it is possible to defend yourself with a revolver in Colt 45. With that said, in the 21st century, a black powder revolver from 1871 would certainly not be our first choice for defensive firearms. Revolvers suffer generally from a lack of capacity, this isn’t the most accurate round in the world, and the smoke cloud from the black powder will make self defense more difficult.
History Of the 45 ACP Cartridge
By the turn of the 20th century, the United States Military realized that the handguns they had been using, in some cases since the 1860s, were showing their age in terms of accuracy and firepower. This was especially clear in light of the lack of the ability for the .38 caliber rounds the United States Military had been using in their recent adventure in the Philippines to penetrate the body of enemy combatants and guarantee an end to the fight.
In 1904, John Browning, working then at Colt, designed the 45 acp to gain a major increase in stopping power, accuracy, and functionality in military pistols. When compared to the older .38 round and fired out of a similar length barrel, the 45 acp brought pistols into a whole new era in terms of stopping power.
Another John Browning design, the 1911, would bring this new cartridge to life in military circles. A cartridge by itself is of no use to shooters, it needs a weapon from which to be fired, and Browning more than delivered with the iconic Colt 1911.
At the time, many police and military shooters had been using revolvers as their secondary, or even primary, firearms for decades. When fully loaded, this limited them to, at most, six rounds: this will only let you fire for a moment or so in a serious fight before you have to reload, which was itself a difficult process usually requiring the use of several accessories such as moon clip or a spare cylinder.
The 1911, then offered a new concept of the firearms world: a handgun that fired a large bullet with a great deal of accuracy, that could hold more than six rounds of ammunition, and was reloaded via magazine. In terms of functionality, it is difficult to understate how much these new pistols, firing the new 45 automatic colt pistol round, changed the world of shooting forever.
Now, over a century later, the rich history of the 45 acp is still being written, and we’re going to go on to recommend a wide selection of handguns in this cartridge that we think are more than viable options as serious carry pistols well into the 21se century.
The Best 45 ACP Handguns
There are a lot of awesome brands that make great guns in this caliber. Instead of leaving you to browse for yourself, we’ll offer you some of our recommendations. From there, feel free to go on over to the website for each of the brands to see what kind of 45 acp handgun is worth your time, money, and ammo.
Here, we’ll cover several different types and brands of 45 acp pistol, before making our final pick for what we think is the best 45 acp pistol overall.
Springfield Mil-Spec 1911
There’s a lot of competition in this space, but here we think that the Springfield Armory Mil-Spec Series of 1911s are an excellent throwback that’s a sign that people appreciate the history of the 1911.
In this series, you can expect the pistol to have all of the old great features of guns from around the WWII period, and Springfield Armory has decided, additionally, to include the grip safety, which some folks do not love, but we don’t mind.
While the sights are fixed on these, it’s possible to adjust both front and rear sights if you have some of the right tools. Additionally, the wood grips can be changed out, though we don’t think you’ll want to in that a gun this classic looks a little bit off with a plastic grip, in our opinion.
Sig Sauer P320 Nitron Compact
We have no issue carrying a 1911, but given that the sights are hard to adjust and some of them can be sensitive to different brands of ammo, we’re going withe the Sig Sauer P320 Nitron Compact for our choice in concealed carry guns here.
With the rail to attach accessories, as well as the military adoption of the P320 series, we’re taking this as a sign that this line of pistols is here for the long haul, and thus we’d be more than willing to carry one. Right out of the box, these are excellent carry guns and you can likely find a model that you’ll like: most people will feel fully covered with a P320 of some kind or another in 45 acp.
Sig Sauer is also known for having excellent customer support, either through their website or on the phone, so even if your example does run into an infrequent issue, they’ll either fix it or replace it with an updated model to make sure that you have a reliable firearm.
Sig Sauer P220 Elite
Here, we’re going with another Sig Sauer gun, in this case the Sig Sauer P220 full size in .45 acp. At this point the gun is growing a little long in the tooth when compared to some of the newer 9mms out there: we do wish you could adjust the sights more, but Sig included excellent ones in the box.
The P220 is one of the models that put Sig Sauer on the map, and we see why: these shoot well, point easily for most shooters and are not nearly as sensitive to ammo types as some of the older models of 1911 can be. We’d feel more than covered if we had to carry this firearm on a daily basis.
Springfield Vickers Tactical 1911
Heading back over to Springfield Armory for this one, we’re going to recommend their Vickers Tactical models if you want to get into shooting competitions. Larry Vickers, who was in Delta Force before being a renowned gunsmith and historian in his own right, has worked Springfield to bring to you an excellent 1911.
At each point, these guns exude quality, and it’s likely all you’ll have to do to get it shooting well for you is to test it with some ammo and adjust the sights to your eyes. From there, it’s likely that you’ll end up customizing it more as you grow as a competitor, but that’s to be expected.
Springfield Garrison 1911
Since we are, in fact, history buffs as well, our pick here is going to the Springfield Armory Garrison series of 1911s. While we love the old style of the heritage models, the extra support of an extended beavertail, as well as the much-improved sights and trigger make this our choice in 1911s, and the .45 acp overall.
Some folks will not like the idea of carrying a gun that only holds 7 rounds of ammo, but with some training, we think this is more than adequate, and, if in doubt, you do have the option of stowing a second magazine somewhere handy.
45 Automatic Colt Pistol Terminology
Synonyms and Misspellings
You’ll notice that the .45 Colt Automatic Pistol, or 45 acp, goes by a lot of different names. With that in mind, we’d like to take a moment to list all of the various ways that people refer to this same cartridge, which should have the same dimensions and performance across various brands.
While confusingly similar in name, the 45 ACP shouldn’t be confused with the 45 Colt Cartridge.
Synonyms For the 45 acp include:
- 45 acp
- .45 acp
- 45 auto
- .45 auto
- 45 automatic
- 45 auto colt
- 45 Colt Automatic pistol
A quick note: the period before the 45 acp is nodding to the fact that what we’re referring to is the caliber, which is measured in hundredths of inches. Thus, the diameter of the barrel of pistols that fire these rounds is 45 hundredths of an inch. With that background in mind, there are a few misspellings of the cartridge that we see sometimes that are worth using when you’re browsing a website looking for promotions or other good deals when you’re thinking of purchasing some 45 acp.
Popular Misspellings for 45 acp include:
- 45 apc
Another note: we assume these are usually mistakes by site managers, as people’s fingers get a little fast on the keyboard sometimes you can’t always expect a website writer to get things right, and people do forget to run spellcheck from time to time.
45acp vs 45 auto
.45 ACP is just another name for the .45 Auto. They are the exact same cartridge and anything labeled in one will fit the other.
45 ACP Vs 9mm Comparison
Comparing these two handgun rounds head to head in terms of a single bullet, there are a couple of trends to keep in mind.
The 9mm is light when compared to 45 acp, but tends to leave a barrel of the same length at greater velocity. Both of them are common pistol rounds and can be found in a wide variety of guns.
|45 ACP||9 mm Luger / Parabellum|
|Case Type||Rimless, Straight||Rimless, Tapered|
|Bullet Diameter||.450 in (11.4 mm)||.355 in (9.01 mm)|
|Case Length||.898 in (22.8 mm)||.754 in (19.15 mm)|
|Overall Length||1.275 in (32.4 mm)||1.169 in (29.69 mm)|
|Case Capacity||26.7 gr H2O (1.73 cm3)||13.30 gr H2O (0.862 cm3)|
|Max Pressure (CIP)||19,900 PSI (137 MPa)||34,084 PSI (235 MPa)|
|Max Pressure (SAAMI)||21,000 PSI (140 MPa)||35,000.00 PSI (241 MPa)|
9mm does also tend to be slightly cheaper, so if the cost per round is something that matters to you, you can find more price-sensitive ammunition in 9mm.
Guns in 45 acp also tend to have a lower capacity than those in 9mm, where round counts up to 20 are becoming more popular.
In general, people choose the 45 acp cartridge for their handgun because they like the background of the 45 acp in terms of history, and often have loyalty to the brands of firearms that are sold in this caliber.
Although 9mm might well be lighter if weight is a concern to you, 45 acp will enable the shooter to have some of the most powerful handgun ammo to be commonly fielded, which is why it’s still a popular caliber among people who are looking into purchasing a pistol for concealed carry in 2021. even though its an older round, we have not met anyone who would want to be shot by a 45 acp, and it’s also more than capable of taking large game.
45 ACP vs 45 Super Comparison
As you can surmise from the previous section the functionality of the 45mm is somewhat in question in you compare it to a more contemporary caliber like 9mm.
With that in mind, there is one cartridge that tries to take advantage of some of the functionality of the 9mm., especially the higher velocities of some brands, and enable shooters to update the 45 acp to something new.
In particular, one such cartridge is the 45 super. Basically, 45 starts with a similar caliber, but heavier weight bullet when compared to the 45 acp, but uses a thicker cartridge casing and much higher-pressure powder to enable substantially higher velocities when compared to a standard 45 acp round. On average, most brands of 45 super will give you several hundred feet per second higher muzzle velocities than a standard 45 acp loading.
|45 ACP||45 Super|
|Bullet Diameter||.450 in (11.4 mm)||.451 in (11.5 mm)|
|Case Length||.898 in (22.8 mm)||.898 in (22.8 mm)|
|Overall Length||1.275 in (32.4 mm)||1.275 in (32.4 mm)|
|Max Pressure (SAAMI)||21,000 PSI (140 MPa)||28,000 psi (190 MPa)|
While it’s not the most common cartridge in the world, it’s vital that you do not forget that 45 acp and 45 super are not interchangeable. The super should not fit in a 45 acp pistol, but if you happen to have something odd like an extremely worn 1911, we cannot recommend, under any circumstances, using the .45 super caliber in guns meant for .45 acp. Doing so would likely result in a major failure in the gun, and would leave you having been effectively shot by a piece of the gun leaving backward at high velocity.
.45 super is a modern update for the .45 acp line of ammo, and we think that if you are committed to 45 acp, but want more velocity and do not mind lower capacity than a 9mm, then it can be a good option for ammo for you.
Best Uses for 45 ACP Handguns
While 45 ACP might not have the same velocity as 9mm, one major benefit of this relatively slow round is that it is less likely to penetrate surfaces like walls. This makes this caliber, in our view, an awesome choice for self-defense at home, where you might be concerned about using a gun if it means bullets going through walls.
Also thanks to its being relatively slow, and depending on the length of the barrel in your pistol, it’s also possible to get 45 acp to fly slower than the speed of sound. This makes a gun in this caliber an awesome candidate for a suppressor, which is an accessory that some folks quite like for home defense.
Some designs, such as more standard 1911s, have several safeties built into them, which also makes them difficult to shoot without knowing what you’re doing. We like this in home defense guns, since you can’t always be at the same site as your gun, and we feel a lot better about leaving a 1911 in a drawer at home than, say, a 9mm Glock with only a trigger safety if there are children in the home at all.
Some folks think that the 45 acp has seen its best days, and it isn’t suitable for concealed carry largely because of the relatively low capacity of most guns in this caliber.
We disagree with that thinking and instead urge you to concealed carry the gun that you shoot the best. For some of us, that’s a 1911 or something similar in 45 acp. A lot of self-defense shootings, it’s important to note, are solved with either a single round or just a few, so the ability to put 20 rounds down range might not be that terribly important.
It’s important to consider specific ammo here: always test out different brands to make sure that the ammo you want to carry is one that functions well and shoots accurately in your specific pistol. Purchasing several kinds of ammo is a pain, but it’s worth doing when working out a safe way to concealed carry.
45 ACP is also a popular choice for hunters, and we can see why. Usually, your primary weapon will be a rifle, but in the case that the rifle either malfunctions you need to humanely dispatch game, then a gun in 45 ACP might be exactly what you want.
This is especially true, we think, if you like backpacking and might not want to carry a rifle: purchasing a handgun that is capable of defending you against large animals makes the 45 acp a sensible choice for more outdoorsy folks who want some peace of mind a camping site. Some brands offer ammo specific to these kinds of purposes and considering those might be a good idea for ammo choices aimed at this purpose.
Duty or Security Gun
If you work in a field that mandates security as being something more than a “gun-free zone” sign, then you might want to consider one of the many brands of pistol in 45 acp for adding some security to a site or as the piston you carry on duty.
Lots of folks in law enforcement have used this round in the line of duty over the last century, and we think it will do well for you well into the future as well: a pistol in 45acp is a great companion when situations go sideways on the job.
In many countries around the world, a 1911 or something similar is a common sign of authority or a badge of office. They’re also awesome handguns in their own right and shoot well.
In some regards, carrying or owning a pistol that shoots this ammo is a nod to that long historical background, and we like to think about that when we browse for a new gun to think about making a purchase.
In this piece, we started with the history of the Colt 45 cartridge. In its original form, with revolvers that were issued to various forces, it was one of the cartridges that remade the American West.
Now, nearly a century later, it’s showing its age and does not, in the original loadings, compare favorably to more modern defensive options.
With that said, if you do want to buy a gun in .45 Long Colt, there are awesome examples out there that can more than help you scratch the itch to eel a little bit like a cowboy.
Is 45 auto the same as 45 acp?
Yes, the .45 ACP and .45 Auto are different names for the same cartridge. ACP stands for “Automatic Colt Pistol.” 45 Auto is a shortened version of this name.
George has been an avid shooter for twenty years. He began shooting when he was gifted a Browning SA-22 for target practice. Now, as an academic, he combines his love of firearms and knowledge of history to write for firearms blogs and is still a frequent sight at the local range.