why is 38spl so slow compared to 357 mag and 9mm?

[300WSM]

ok so couple of questions...

first why is 38spl +p so slow compared to 357mag. Case size seems to be about the same.

2nd why aren't 38spl faster then 9mm? 9mm is a much smaller case yet is faster?

Sorry for the newbie question.

http://tinypic.com/r/2enqjv7/5 9mm 115gr 1250fps, 38spl+p 110gr 1050fps, 357mag 125gr they have it loaded at 1300fps but I've seen them around 1450, 357sig 125gr 1350fps.

 

[Ares]

Re: why is 38spl so slow compared to 357 mag and 9mm?

.357 Mag case is longer and you puts more powder in it

.9mmL is shooting from losed chamber but when shooting .38 SPL a bit of gases goes away between chamber and barrel

And in .38 SPL is powder to only about half of it

 

[Lindy]

Re: why is 38spl so slow compared to 357 mag and 9mm?

For the same reason that a .300 Winchester Magnum is faster than a .308 Winchester.

The faster cartridges are intended to be fired in weapons designed to withstand higher pressures.

You can have as much power as you want. Higher powers are accompanied by more recoil, and usually by heavier weapons.

 

[michael_aos]

Re: why is 38spl so slow compared to 357 mag and 9

Because the 38 Special is a low-pressure cartridge that was originally a blackpowder load that dates back to 1899.

Lots of info in Wikipedia

 

[300WSM]

Re: why is 38spl so slow compared to 357 mag and 9

357mag is only a tad longer than 38spl +p but 38spl is around 1050fps with 110gr and 357mag is 1450 with 125gr doesn't make sense.

and 9mm is way shorter than 38spl but shoots a slightly heavier bullet much faster.

is the case wall thinner or something?

 

[Lindy]

Re: why is 38spl so slow compared to 357 mag and 9

The case of a .357 magnum is longer, so that it won't chamber in .38 Specials. The case capacity is irrelevant, because pistol powders are fast enough that you can load a .38 Special case to .357 magnum velocities. It just isn't a good idea - unless you're going to fire it in a .357 magnum pistol.

And, actually, it still isn't a good idea, because you might stick those rounds accidentally in a .38 Special and blow it up.

 

[ChadTRG42]

Re: why is 38spl so slow compared to 357 mag and 9mm?

It's all about the pressure of the round. The more pressure you have, the faster you can push a bullet. A 9mm has double the pressure of a 38 Spec, so that's how it is able to push it faster. Most rifle rounds run at about 50K-62K PSI.

38 Special- 17K PSI
38 Spec +P- 20K PSI
40 S&W- 33K PSI
357 Mag- 35K PSI
9mm- 35K PSI
357 Sig- 40K PSI

 

[Fuzzball]

Re: why is 38spl so slow compared to 357 mag and 9mm?

The .38 Spec is OLD, and works at lower pressures.

It was much faster when it was young.

 

[Halfnutz]

Re: why is 38spl so slow compared to 357 mag and 9mm?

My take on it...
A .38 spcl cartridge loaded today has to safely operate in the first pistol designed to fire it.
Eventually someone wants faster i.e. a .357...metalurgy is improved, powders are improved, firearm design is improved, whatever. Now you have to "idiot proof" your new cartridge so that even though you coulda done it with a NEW .38 it now needs to be seperated physically from it's unsafe predacessor. (my former boss said to refer to it as "Fail Safeing")(it's not politically correct to call an idiot an "idiot"). Which is the long version of what Lindy said.

You wil see in your reloading manuals loads for "Modern" firearms in cartridges such as .45-70 and a seperate section for "vintage" firearms. It all has to do with the pressures the gun was designed with which to operate safely.

 

[Fuzzball]

Re: why is 38spl so slow compared to 357 mag and 9mm?

"...you have to "idiot proof" your new cartridge..."

Every time someone fool proofs anything the world comes up with a more capabile fool. Many .38s have been blown by those trying to duplicate .357 ballistics. Oh, well, it does tend to improve the gene pool.

Ref. the vaunted 9mm, all it amounts to is a .38+P loaded with light bullets.

 

[Queequeg]

Re: why is 38spl so slow compared to 357 mag and 9mm?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">"...you have to "idiot proof" your new cartridge..."

Every time someone fool proofs anything the world comes up with a more capabile fool. Many .38s have been blown by those trying to duplicate .357 ballistics. Oh, well, it does tend to improve the gene pool.

Ref. the vaunted 9mm, all it amounts to is a .38+P loaded with light bullets. </div></div>

Well I avoid all of this by making my 9mm reloads run at .357 sig pressures. See you all on the other side... Well, maybe half of you...
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Kidding