how do the calibers of ammunition work?

Question

For instance: what is the difference between .38 and .380?

Answer 1

Bound's hubby here:

In very basic terms, 99% of the cartridges that exist today are unique and not interchangeable. The first set of numbers identifies the bullet's diameter. Any subsequent numbers may identify such things as: the parent cartridge, the cartridge velocity, or the year of development. The names that follow the numbers is typically the person or organization that developed that cartridge design. Subsequent names (adjectives) may describe may describe a modification to the orginal cartridge, power level or type of cartridge case.

There are many different cartridges out there. To discuss all of them here would probably shut down the site. If you want to learn more about the cartridges in general, pick up a copy of the book called "Cartridges of the World".

Good luck.

Answer 2

This is a complex matter. Caliber is theoretically the diameter of bullet or bore, but a rifled gun has two diameters (across lands and across grooves), and either may be used. The .38" has been around longer than the .380". Newer calibres may have more precise measurements. Actually, a .38Colt or Special is a .357, and a .380ACP is a .355. You surely know that millimeters may be used rather than decimal inches. The .380 ACP is also known as the 9mm Kurz. There is no short cut to understanding the differnces in ammunition. You must just look at a book on cartridges to see when each was invented, the true caliber, the amount of powder used, the case lenth and cartridge length, etc. I suggest that you look at "Cartridges of the World" at libraries and bookstores. It is a good reference work on its subject.I own several editions of it plus reloading manuals that are also helpful. Look at them too.

Answer 3

Unfortunately some individuals (including some "gun nuts" who should know better) use caliber and cartridge interchangeably. For example the .270 Winchester cartridge is a .277 caliber and the .30-06 cartridge is a .308 caliber (as is the .308 Winchester cartridge), and the .280 Remington is a .284 caliber. The caliber refers to the diameter of the bullet, while the cartridge refers to the case/bullet combination. Several other examples have been given in other answers. The .44 Mag and .44 Special cartridges are .429 caliber and the .380 cartridge is a .355 caliber while the .38 cartridge (including the special) is a .357 caliber as is the .357 mag cartridge.

Answer 4

There have been several different methods of using "caliber" since the early nineteenth century. As previously stated, inconsistancy is the rule for caliber naming. The most common, however, has become the method of bullet diameter, but you must be careful in assuming diameters of slugs. Below are some good examples:

Cap and ball revolver caliber:

.36 caliber=.375"
.44 caliber=.451-.454"

Late Nineteenth Century

.38(ex. .38SW)=.360"
.41(ex..41Colt) =.386"
.44(ex.SW Russian) =.429"
.38(ex..38Colt) =.357"

20th Century

.45(ex. .45ACP)=.451-.452"
.357(ex..38SWSPL/.357MAG)=.357"
.40/10mm=.401"
.41(ex..41MAG)=.411"

This partial listing gives you an idea of what went down with measurement through history. Note how .429" (44) and .357" (.38) were born in the late nineteenth century. These nominal dimensions would carry over into the 20th century(44SPL/.44MAG or .38SPL/.357MAG are examples). At least with the .38 caliber (both .357 and .360), brass case diameter was measured to give caliber (.379" becomes .38 caliber). So caliber was not always based on bullet diameter!

Answer 5

Unfortunately, there is no consistent system. You pick it up as you go along. The "38" gives you a rough idea of bullet size, but to know the cartridge you have to learn each individually. It's a reasonably safe bet that a 38 caliber cartridge is going to have a bullet with a larger diameter than a 22, and smaller than a 45, but that's about as far as the system goes. For instance, the 38 Special shoots a bullet .357" in diameter, but the 38 Winchester Center Fire uses one .401" and that's just talking about the bullet. Most cartridges begin as proprietary things and the company's marketing strategy has a lot to do with the naming of the cartridge. A good example is the 280 Remington, which shoots a .284 bullet. It was introduced to compete with the popular 270 Winchester (.277 bullet) but initial sales were slow. They renamed the cartridge "7mm Express" to try to gain market share, but that confused some people who knew about Remington's 7mm Magnum, so they went back to the original name. If you know anybody who handloads his ammunition, browse one of the handloading manuals and you'll get a good overview. One of your buddies may also have a copy of Frank Barnes's book "Cartridges of the World," another good starter for explanations.

Answer 6

The "caliber" you see advertised was made for marketing purposes. The difference between calibers is usually the size of the bullet, case, and how much powder is in the case.

The difference between those two is usually:
the .38 is a rimmed cartridge, where .380 is not.
the 38 is about an inch long, .380 about .75 inches long
the grains of powder in case are different
the bullet diameter are the same......

Answer 7

In most cases the smaller the number the small the cartridge/round/caliber or bullet, here are some of the popular rounds for example.

22LR
25 Auto
380
9mm
40 S&W
357 Mag.
44 Mag.
45 ACP This is the more popular handgun rounds.

223 Rem.
243
270 Win.
30-30
308
30-06
35 Rem
7mm-08
7mm Rem Mag.
300 Win Mag.
338 Mag. and last of all a small ist of the popular rifle rounds.

Hope this helps.

Answer 8

the caliber is the diameter of the bullet using inches and mm to measure the bullet. exampole:a 45 means a 45/100th of an inch. or a .30 means a 30th of an incs.

Answer 9

Most likely it is in the shape or length of the case that holds the round that makes the difference. You will need a good set of calipers and/or micrometer to tell the differences.