Why do guns come in their calibers?

[delta9]

Why did the designers pick the various calibers that most guns come in?

Why did they decide on .223 rather then .22 or .25?

How is .357 the same as .38?

[russ69]

Why .223? Because the .222 was not enough and the 222 Rem Mag was too much. There are books about why this happened, a little hard to define in a couple of paragraphs. Buy a reloading book and read up on the history of each cartridge. There are a lot of things to learn.

[Dead*Reckoned]

Its sort of like asking why certain cars are more popular than others.

[shellyzsweet]

Cause variety is the spice of life. Some people prefer smaller projectiles with less recoil and have a great number of rounds. Some prefer larger with more recoil or a recoil their used to with fewer rounds. All rounds preform differently just like all cars preform differently.

Personally I think NATO needs to move to 6.5 or 6.8 and away from 5.56, but then again, its all about shot placement anyways

[Eljay]

It's historic. Somebody will see a gap in the market and produce some new cartridge and some gun to use it and it will catch on or it won't. Sometimes it's driven by the military and sometimes civilian markets. Sometimes it's very artificial like in some countries they can't use military calibers so they'll use something slightly longer or shorter.

If you want an example the military used .30-06 for years (.30 cal, 1906 specification), and then at some point with modern powders they realized they could shorten the brass and use the same bullet and the same ballistics. So Winchester started marketing .308 and two years later NATO adopted something almost identical in metric as 7.62x51mm.

[Eljay]

Also re: "How is .357 the same as .38?" - I believe one measurement is from land to land and the other is from groove to groove. You shouldn't take the caliber names too literally - they basically just are trying to distinguish from existing ones and they'll play whatever games they need to.

[joelogic]

Its just marketing. 5.7L does not equal 350ci. 5.0 is not a 302.

[Fishslayer]

How is .357 the same as .38?

It's not.

Oh wait! You mean the bullet diameter!

Here ya go...

http://en.wikipedia.org/wiki/.357_Magnum

[hk91666]

It's historic. Somebody will see a gap in the market and produce some new cartridge and some gun to use it and it will catch on or it won't. Sometimes it's driven by the military and sometimes civilian markets. Sometimes it's very artificial like in some countries they can't use military calibers so they'll use something slightly longer or shorter.

If you want an example the military used .30-06 for years (.30 cal, 1906 specification), and then at some point with modern powders they realized they could shorten the brass and use the same bullet and the same ballistics. So Winchester started marketing .308 and two years later NATO adopted something almost identical in metric as 7.62x51mm.

That was after arthur savage developed the 300 savage which is the father of the 7.62x51 - 308 winchester

Sent from my SAMSUNG-SGH-I317 using Tapatalk 2

[russ69]

Also re: "How is .357 the same as .38?" - I believe one measurement is from land to land and the other is from groove to groove.

Ah, no. The 38 special and the 357 magnum use the same exact bullet and bullet diameter. The projectile is exactly .357 inches in diameter. The names of the cartridges are from the mind of the marketers, that's it.

[Eljay]

Ah, no. The 38 special and the 357 magnum use the same exact bullet and bullet diameter. The projectile is exactly .357 inches in diameter. The names of the cartridges are from the mind of the marketers, that's it.

I'm not talking about the dimensions of the bullet. The lands and grooves are part of the barrel. It used to be normal to discuss calibers in terms of barrel dimensions, not bullet dimensions. This is a nomenclature shift that happened at some point. (Although it turned out to be a wrong guess for this particular caliber - see my post below)

[hermosabeach]

38 special vs .357 mag

The 38 special had been around for years. Some people were trying to make it more effective by speeding up the bullet.

The .357 has a longer case than the .38 so you cannot load the higher pressure cartridge in a .38 special and damage the gun and or shooter.

They made the .357 maximum which was an even longer case. They found that the extra velocity wore out the barrel quickly and the cartridge died out.

The .44 special was the same evolution. A fine legions from Montana, Elmer Keith, was loading very hot loads in the .44 special and was shooting big game with the load. Smith and Wesson made the round into the .44 mag. Again with a longer case so that it can or be loaded into the .44 special gun

And yes- you can shoot .44 specials- the low pressure rounds- from a .44 mag
The same holds true that you can shoot .38 special from the .357 mag

After black powder was replaced by modern smokeless powder, guns had to be redesigned to handle the higher pressures.

A lot of the popular cartridges we shoot today go back to around 1900

Just as the .38 and .357 are variants.... The same is true with rifles

The 30-06. That is .30 caliber adopted by the US military in 1906 is necked down to make the .270. It uses the same base brass but the bullet is .270 in diameter, not .30.
Why-
The manufacturers can use the same equipment and built the same gun with a different barrel- cost effective
The .270 shoots a ligher bullet- faster than the 30-06 and faster means less drop over the same distance. So for hunting, range estimation out to hunting distances is easier

The .308 Winchester was also necked down to .243 (6mm) to form the .243 Winchester

There are lots of good books and videos that document the evolution of modern cartridges

[Eljay]

I looked up the full story behind the .38. It's perverse.

"Despite its name, the caliber of the 38 Special cartridge is actually .357–.358 inches (9.0678 mm), with the ".38" referring to the approximate diameter of the loaded brass case. This came about because the original .38-caliber cartridge, the .38 Short Colt, was designed for use in converted .36-caliber cap-and-ball (muzzleloading) Navy revolvers, which had cylindrical firing chambers of approximately 0.374-inch (9.5 mm) diameter, requiring heeled bullets, the exposed portion of which was the same diameter as the cartridge case (see the section on the .38 Long Colt)."

http://en.wikipedia.org/wiki/.38_Special

[Merc1138]

History, marketing campaigns that worked so well people forgot things never existed(like .40s&w vs. 10mm), people looking to fill or create a niche(fn 5.7, .357sig, hk 4.6, .22tcm, some of the .17 cartridges, etc.), people looking to adapt something(again see .40s&w vs. 10mm) to work for/in something else, carrtidges becoming outdated but retaining popularity(sometimes because there were just so many guns made, sometimes because people found a new niche)...

The list goes on and on. You could ask about the same reason there are so many different types of screwdriver bits/screw heads, 50+ different sizes/voltages of batteries for small electronics, etc.

[hermosabeach]

More random thoughts-

The 9mm parabellum goes back to 1901
The .45 ACP goes back to around 1903/1905

We had a historical Miami shoot out with the FBI and Bankrobbers in 1986.
At the end of the day, the FBI looked at the failures to stop and there were some outcomes.

The FBI had been using the 9mm as the .45 had too much recoil for some officers.
They wanted a more powerful round and the 10mm (.40 caliber bullet diameter)showed promise

As the 10MM has a fair amount of recoil, they loaded the round to a lower pressure.

The .40 S&W is basically the FBI load. It is a shorter cartridge so it fits in the same size frame as the 9mm. This smaller frame fits many people's hands better in a double stack than the .45/10mm frame. It also has recoil that is managable by most shooters

The other outcome from the FBI studies of the 86 shoot out was good hollow point ammo
Bullets that would consistently expand we're not common pre 1986. Well not in semi auto handguns