.357 magnum vs. .38 special diameters

[jcisbig]

I've been trying to do some research and info's a little hard to come by. I've got a .357 mag and it shoots both .357 and .38 special ammo, and I'm wondering exactly why those two 'calibers' can both fit into the cylinder? Is there a size difference between the two? Is there not? Are the bullets the same diameter and the casings not? Just looking for a little clarificaiton! Thanks!

[jdlv4_0]

They are both the exact same diameter, you are correct, the casing of the .357 is longer, and I'm not 100% but the average bullet weight may also be different.

[danp]

From: http://www.recguns.com/Sources/IIIB4.html

Even though most ammunition "names" such as .22, .25 and .38 refer to the diameter of the round expressed in decimal inches, the .38 Special and .357 Magnum rounds are the same diameter. The differences are in length, powder loading and bullet size and weight. In those aspects, the .357 Magnum is bigger, heavier and more powerful.
All revolvers manufactured to use .357 Magnum ammunition can be safely loaded and fired with .38 Special ammunition. The reverse, obviously, is not true. You cannot use .357 Magnum ammunition in a .38 Special weapon.

[jcisbig]

Thanks for the info! My quesiton then is, who thought to call a round with a diameter of .357 a .38 special? Why not a .357 special?

[Frenchy]

Originally Posted by jcisbig

Thanks for the info! My quesiton then is, who thought to call a round with a diameter of .357 a .38 special? Why not a .357 special?

Actualy the original round was called the 38 Smith In the chart below you can see how it was much smaller then the modern 38 SPL. The casing was also tapered much like the 9mm is today. the average of the taper was 38/1000 or an inch, hence the name 38. Other bullets later where made by Colt and other manufacturers. But the ones that stuck where the 38 SPL, the 38 +P and the .357 There is also a 38 Super auto that is fairly popular. If you click on the chart below it will go a bit larger so you can read it. 30 Smith is the third row, third bullet, 38spl is 5th row last bullet, you can see the size differance.

[The Drew]

What you should take away from this discussion is that a cartridge name doesn't always denote it's dimensions.

9x18m is another example, it's actually something like 9.2mm not 9mm

same goes for .380auto it is actually about .357 in diameter not .380

[jcisbig]

I guess overall it just seems inconsistent to me. A cartridge should be labeled as it is, and not have a 'misleading' dimension attatched to it. But hey, I'm not an ammo manufacturer!

[ChamberedRound]

Originally Posted by jcisbig

I guess overall it just seems inconsistent to me. A cartridge should be labeled as it is, and not have a 'misleading' dimension attatched to it. But hey, I'm not an ammo manufacturer!

Modern cartridge based ammo has been around for 120+ years, and during that time conventions changed more than once, hence some of the confusion. For example, some ammo is labeled based on the bullet diameter, whereas others are labeled on the overall case diameter. Why? Because that's just the way the people who invented the ammo decided to do it. Is it confusing? Yup.

Originally gun manufacturers and ammo manufacturers were one in the same; the people making the gun made a cartridge/bullet/load specifically for that gun. That's why the 1911-style pistols shoot .45 Auto, also called .45 ACP (Automatic Colt Pisol); it was a bullet which was originally designed specifically for the Colt 1911. Not to be confused with the .45 Colt, originally designed for the Colt Single Action Army Revolver. Same diameter, different cartridge. Another example is the 9mm round, also called 9mm Luger, to differentiate it from other 9mm rounds, like the 9mm Makarov (9x18).

In the end, the people that invent the round can call it whatever they want, and we need to decipher it.

[Biggfoot44]

The most commonly accepted account is that in the very begining of selfcontained cartridges, they most commonly used heel type bullets, now seen primarily in .22 rimfires. In this type the diameter of the bullet is the same as the outside diameter of the casing. Then after inside seated bullets were introduced (generally considered to be the S&W .44 Russian circa 1869) other mfgs saw the superiority of the situation. For the most part, the case sizes and designations were retained, and bore size was reduced slightly to corespond. There were a few transitional oddities, most notably the .41 Colt family of ctgs, but that's a seperate line of trivia.