Most Important & Common Bullet Calibers Explained

Ammo relates to all the materials fired, dropped, scattered, or detonated from a firearm or a similar system. It embraces multiple forms and could be used with expendable weapons, as well as parts of various weapons that create certain effects.

The overall goal of ammunition is to project a particular type of force against a target. Simply put, a firearm is useless without ammo. Now, different firearms require different types of ammo. It comes in all kinds of sizes and shapes and will only work for specific weapon systems.

With these thoughts in mind, here’s a list of calibers and the unique particularities of each of them.

Rimfire cartridges

Rimfire ammo features a primer located in a hollow rim and a mechanism that will ignite a propellant in the case. It was invented by Louis-Nicolas Flobert in 1845.

• .17 PMC/Aguila is basically an updated version of the .22 Long Rifle casing, modified to take .172 inch bullets. It was introduced in 2003.
• .17 Hornady Mach 2 was first made in 2004 by Hornady. It’s sometimes referred to as .17 HM2 as well, and it's known for its impressive velocity.
• .17 Hornady Magnum Rimfire is often referred to as .17 HMR and offers great velocity at over 2,650ft/s. It's been in production since 2002.
• .17 Winchester Super Magnum was made by Winchester in 2012 and represents the successor of the .27 caliber nail gun blank cartridge.
• 5mm Remington Rimfire Magnum, also known as 5mm RFM, is a bottleneck cartridge designed in 1969. It’s still in production today.
• .22 BB Cap is often sold as a 6mm Flobert, too. Designed in 1845, it’s still widely used today due to its reliability.
• .22 CB Cap is similar to the .22 BB Cap cartridge, but it’s more powerful. The two cartridges can be interchangeable.
• .22 Short was made in 1857 and represents the first metallic cartridge in the USA. It was known as .22 before long and short variants appeared.
• .22 Long is a variety of the same cartridge. Made in 1871, it’s one of the oldest surviving rimfire cartridges.
• .22 Long Rifle or .22 LR is a long variant of the .22 cartridge and can be used in submachine guns, pistols, revolvers, and rifles.
• .22 Extra Long is mainly used in rifles and handguns. It was officially made between 1880 and 1935, so it’s nearly impossible to find today.
• .22 Remington Automatic was initially made for Remington’s Model 16. It’s never been used on other firearms.
• .22 Winchester Automatic was exclusively made for Model 1903 from Winchester. Like Remington’s proprietary cartridge, this one hasn’t been used on other rifles either.
• .22 Winchester Rimfire has a flat nose slug, which is the only difference between this cartridge and .22 Remington Special. Its role was to help against small games.
• .22 Winchester Magnum Rimfire has been in production since 1959. It was produced by Winchester, but it went into use a few years later when Winchester actually had a rifle for it.
• .25 Stevens was mainly produced throughout the first half of the 20th century. It was made for a few rifles, but some handguns could also use it.
• .25 Stevens Short was produced between 1902 and 1942. Compared to the classic .25 Stevens, it was cheaper and more powerful.
• .32 rimfire covers a whole family of cartridges made during the 19th and 20th centuries. The production was mainly ceased during World War II.
• .38 rimfire is larger than the .32 rimfire, so it gained more popularity. It’s still being used by various military branches in the USA.
• 10.4×38mm Swiss Rimfire was made during the 19th century and came as an upgraded version of the 10.4x38mmR cartridge.
• .44 Henry is known by more names, such as .44 Henry Flat or 11x23mmR, among others. It’s used in both rifles and handguns.
• .46 rimfire covers a whole set of cartridges made in multiple sizes, used in rifles and revolvers. The production ceased in 1917.

It's also worth noting the .56-46 Spencer, .56-50 Spencer, .56-52 Spencer, and .56-56 Spencer cartridges, mainly designed for Spencer firearms.

Centerfire cartridges

Centerfire gun calibers go in more categories, but they’re most commonly organized by their sizing standards.

Smaller than .30 caliber

Centerfire cartridges are extremely diversified, being produced by numerous manufacturers. Here are some of the smallest ones.

• .14-222 is an adjusted .222 Remington and was created in 1985.
• .17-223 relies on the .223 Remington case, but the neck has been modified for the .17 caliber bullet.
• .17 Ackley Bee carries the designer’s name and was mainly popular among single shot rifle users.
• .17 CCM was introduced in 1992, but it went through a few modifications overtime.
• .17 Hornet is often referred to as a wildcat cartridge and is better known for its velocity.
• .17 Mach IV borrowed the .221 Remington Fireball. It was designed in 1962.
• .17 Remington was specifically made for the Model 700 rifles designed by Remington.
• .17 Remington Fireball was designed by Remington as the main competition for the .17 Mach IV.
• .19-223 is one of the few cartridges developed by James Calhoon and has an excellent trajectory.
• .19 Badger is part of the same group of Calhoon cartridges, but it’s slightly better than the others.
• .19 Calhoon Hornet is practically a modified version of the .22 Hornet cartridge.
• .20 BR is known for its high efficiency and accuracy due to its short fat case.
• .20 Tactical can achieve great velocity with less powder than other similar cartridges.
• .20 VarTarg is designed for small rifles, but there’s also a .20 VarTarg Turbo variant.
• .204 Ruger dominated the market after its initial design from 2004. It’s still in production today.
• .22 Accelerator is produced by Remington, and while it has great velocity, accuracy is sacrificed.
• .22 Hornet is a cartridge designed for survival and small game hunting rifles.
• .22 CHeetah is a modified .308 BR Remington cartridge designed by Fred Huntington and Jim Carmichel.
• .218 Bee is ideal for varmint hunting. It was designed in 1937.
• .219 Donaldson Wasp is based on the popular .219 Zipper. It was designed in 1940.
• .219 Zipper was designed for Remington’s Model 64. The production ceased in 1962.
• .303/22 features the original .303 British design but with a few improvements for small game hunting.
• .22 Savage Hi-Power was often known as 5.6×52mmR and mainly made for Savage Model 99.
• .22 BR Remington is mainly used for practice shooting and varmint hunting sessions.
• .22 PPC was designed in 1974 and represents a variation of .220 Russian.
• .22 Remington Jet was produced by Smith & Wesson and Remington in a joint project.
• .22 Spitfire was initially named MMJ 5.7mm. The concept was designed in 1963.
• .22 WCF is a relatively small cartridge, mainly used for Winchester’s Model 1885.
• .220 Russian was mainly used for deer hunting in the Soviet Union. It was designed in 1961.
• .220 Rook was designed by the British at the end of the 19th century.
• .220 Swift has great velocity and was mainly produced for small game hunting.
• .22-250 Remington has an incredible velocity and is mainly used for small game hunting.
• .222 Remington is a classic. It was introduced in 1950 for benchrest competitions.
• .223 Remington is a rimless cartridge widely used all over the world. Quite a few cartridges are also based on it too.
• .224 Weatherby Magnum is most commonly used in shooting competitions.
• .240 Weatherby Magnum was introduced in 1968. It was Roy Weatherby’s last cartridge design.
• .242 Rimless Nitro Express is much longer than .243 Winchester, but the performance is almost identical.
• .243 Winchester is one of the most popular cartridges for shooting competitions.
• .243 Winchester Super Short Magnum was introduced in 2003 and relied on the .300 WSM case.
• .244 H&H Magnum offers a flat trajectory, it’s fast and goes at great speeds, ideal for hunting.
• .244 Remington came out in 1955 and offers an excellent distance for small game hunting.
• .25 Remington is known as one of the most accurate cartridges ever made. Its size makes it suitable for deer and bear hunting, too.
• .25-45 Sharps is relatively new when compared to other cartridges, but extremely useful for North American games.
• .25 Winchester Super Short Magnum is one of the most capable options on the market, suitable for large games.
• .25-06 Remington is often considered a top choice for medium game, but it failed to gain too much popularity.
• .25-35 Winchester is one of the oldest cartridges still in production. It was introduced in 1895.
• .256 Gibbs Magnum was designed for Mauser’s sporting rifles. It has been in production since 1913.
• .256 Winchester Magnum was made by altering the .357 Magnum cartridge and used for small game hunting.
• .257 Roberts offers the perfect middle solution between a low recoil and a flat trajectory.
• .260 Remington has managed to standardize the cartridges based on the .308 Winchester case.
• .264 LBC-AR is an intermediate cartridge with multiple uses, but mainly for the AR-15 platform.
• .270 Winchester quickly became a front runner in terms of a flat trajectory, dominating the market as soon as it was introduced in 1923.

These are by far some of the most popular cartridges smaller than .30 caliber. However, the list is much longer. Some other cartridges are no longer in use, or they've been specifically made for less popular firearms. Here's a more extensive list with these bullet calibers.

• .22 Eargesplitten Loudenboomer
• .221 Remington Fireball
• .22 Nosler
• .222 Remington Magnum
• .222 Rimmed
• .223 Winchester Super Short Magnum
• .224 Boz
• .224 Valkyrie
• .225 Winchester
• .297/230 Morris
• .240 Apex
• .246 Purdey
• .303/25
• .25-21 Stevens
• .25-25 Stevens
• .250 Savage
• .25-20 Winchester
• .297/250 Rook
• .250-3000 Savage
• .255 Jeffery Rook
• .256 Newton
• .257 Weatherby Magnum
• .26 Nosler
• .264 Winchester Magnum
• .270 Weatherby Magnum
• .270 Winchester Short Magnum
• .275 H&H Magnum
• .275 No 2 Magnum
• .275 Rigby
• .276 Enfield
• .276 Pedersen
• .277 FURY
• .277 Wolverine
• .28 Nosler
• .280 British
• .280 Flanged
• .280 Jeffery
• .280 Remington
• .280 Ross
• .284 Winchester

.30 caliber to .39 caliber

Slightly larger and suitable for more intense operations, calibers ranging between .30 and .39 are just as varied and complex.

• .30 Remington stands out because it was a front runner from 1906 until the 1980s. Its case is used for other cartridges as well.
• .30-30 Winchester has been in continuous production since 1895 and was initially used for the brand’s Model 1894.
• .32 Remington is a smokeless powder design, mainly used for large game, bigger than black bear.
• .33 Nosler is one of the six cartridges produced by Nosler. It’s based on the .300 Remington Ultra Magnum and was designed in 2016.
• .35 Remington is the only middle power rimless cartridge from Remington that’s still in production these days.
• .357 Magnum is used by multiple firearms. Designed in 1935, it’s still made today. It’s based on an old .38 Special cartridge.
• .375 Ruger was introduced in 2007 and was made as a more advanced alternative to .375 H&H.

Just like in any other category, there are over 100 different cartridges in this group. Some of them are made for particular guns, others are rare or no longer in production. Here are a few other notable options:

• .30 Carbine
• .30 Newton
• .30 Nosler
• .30 R Blaser
• .30 Remington AR
• .30 TC
• .30-01
• .30-03 Springfield
• .30-06 JDJ
• .30-06 Springfield
• .303-06
• .369 Nitro Express
• .375 CheyTac
• .375 Dakota
• .375 Flanged Nitro Express

.40 caliber to .49 caliber

A larger caliber has many more applications and greater velocity. But like other sizes, calibers of bullets have also evolved overtime.

• .405 Winchester has been in production since 1904 and represents one of the most powerful cartridges for lever action rifles.
• .416 Remington Magnum was specifically made for dangerous game hunting. Given its size, it’s suitable for large games.
• .416 Weatherby Magnum is just as powerful and can be used for very large game, such as elephants or buffaloes.
• .44 Remington Magnum is a large cartridge developed for revolvers.
• .45 Colt was made for American authorities. It’s a handgun cartridge with incredible power, but it’s not in use anymore.
• .470 Nitro Express was introduced in 1907 and is suitable for big game hunting, especially around Asia.

While these cartridges dominate the market, the list is much longer and counts more than 100 cartridges. Some of them are designed with certain purposes, such as .43 Egyptian or .43 Spanish, which were used by certain military forces.

Then, there are also cartridges made for particular firearms.

All in all, here are a few other notable options:

• .401 Winchester Self-Loading
• .416 Barrett
• .444 Marlin
• .450 Nitro Express
• .458 HAM'R
• .458 Lott
• .465 H&H Magnum

.50 caliber or larger

Such large cartridges can take down the biggest animals you can think of. They have incredible power, but their size is not to be overlooked either. These types of calibers are clearly not as common as the ones mentioned above.

.50 Alaskan or .50-70 Government make some excellent examples, but it’s also worth mentioning .500 Nitro Express.

.577 Tyrannosaur, for instance, was designed for dangerous game hunting in Zimbabwe. .600 Nitro Express was particularly made for elephants, while .50-90 Sharps was made for buffaloes.

Other worthy cartridges in this segment include .50 BMG, .577/450 Martini–Henry, .585 Nyati, and .55 Boys, among others.

Other classifications

Centerfire cartridges are also classified by their size in millimeters. Here are the top categories and a few representative rifle calibers.

• Smaller than 6mm: 4.6×30mm, 5.45×39mm, 5.56×45mm NATO, 5.6×50mm Magnum and 5.8×42mm
• 6mm to 7mm: 6mm AR, 6mm Remington, 6.5mm TCU, 6.5×57mm Mauser and 6.8 Western
• 7mm to 8mm: 7mm BR Remington. 7×57mm Mauser, 7-30 Waters, 7.62×51mm NATO and 7.62 Thumper
• 8mm to 9mm: 8mm Lebel, 8×56mmR, 8×58mmR Danish Krag, 8×64mm S and 8.6mm Blackout
• 9mm and larger: 9x19mm Parabellum, 9.3×57mm, 12.7×54mm, 12.7×99mm NATO and 15×115 FN

Handgun cartridges

There are countless handgun cartridges out there, so many that it’s nearly impossible to mention everything on an ammo list. Many firearms calibers have also been designed as prototypes or perhaps for certain handguns in various countries, so keeping track of everything is a difficult job.

Some cartridges are more common, though and these are the ones that make the difference:

• 10mm is rare and has been through a series of changes overtime. It’s considered a total failure, but it still has a loyal following.
• .38 S&W has been used by military forces from all over the world, and it's still a strong option, especially in Commonwealth countries.
• .380 ACP is one of the most fatal calibers of ammo for handguns. It has an interesting design, and it's been used quite a lot throughout history.
• .45 Colt is still an excellent option for handguns despite being around for nearly 150 years. It served as an official cartridge in many military forces.
• .38 Special is similar. It may feel a bit outdated, and it may feel old fashioned, but it's still a good choice for many modern handguns.
• .455 Webley has been designed for the world renowned Webley handguns. It also served throughout both world wars.
• .44 Magnum was famous before Clint Eastwood used it in his western movies. It became an icon, and it can be used for anything.
• .45 ACP is an American icon that has served in wars and conflicts all over the world. It’s one of the most recognizable cartridges in the world.
• .357 Magnum may have lost some of its popularity overtime, but it’s still one of the most versatile cartridges ever made.
• 9mm Parabellum is what most people think about when they look after a handgun cartridge. It’s a popular choice for self defense, but armies from all over the world also rely on it.

Other notable options include:

• 5.45×18mm
• .22 Short
• .22 Long
• FN 5.7×28mm
• .35 S&W Auto
• 8.5 mm Mars
• 9×23 mm Winchester
• .429 DE
• .50 Action Express
• .500 S&W Magnum

Shotgun cartridges

Shotgun firearms calibers are classified in a different manner. Compared to other firearms, shotguns are often overlooked and don’t come in such a wide variety of models.

• .360 bore is among the smallest bores out there, and apart from self defense, it's also used by professionals, such as pest control workers.
• .410 bore is also made for small shotguns. Apart from pest control, such shotguns are also suitable for small game hunting sessions.
• 32 gauge boosts just over half an inch in diameter. It used to be popular at the beginning of the last century, and there are still a few South American and European military forces relying on it.
• 28 gauge is considered a middle option, as well as one of the most popular solutions for shotguns these days.
• 24 gauge is similar. It’s still a popular choice in Europe and South America, but experts would consider it outdated.
• 20 gauge is excellent for those who don’t like too much recoil. In other words, it’s suitable for shotgun newbies.
• 16 gauge has slowly faded away and lost most of its popularity. While still available in commerce, it’s not that common.
• 14 gauge shotguns used to be popular during the 19th century, but with time and the evolution of shotguns, people started disliking them.
• 12 gauge is the most popular option in the world, but especially in the USA. It’s excellent for self defense, as well as both small and big game hunting.
• 10 bore is similar to the 16 gauge option. There was a time when it was a viable option, but it faded away overtime.
• 8 bore was very common throughout the 19th century. It was common in black powder guns. Its origins date back to the UK.
• 6 bore was similar. Back in the day, it was a solid choice. With the evolution of shotguns, it became less relevant.
• 4 bore was most commonly used in the 19th century in big game hunting, but particularly against dangerous and large animals.
• 2 bore has a relatively low velocity, and it's no longer useful in today's market.

Bottom line, these are only some of the most popular bullet calibers out there. Gun calibers have evolved a lot over the past centuries, and many of them have been adapted to match modern firearms. Meanwhile, some others passed the test of time and can still be used today.