.357 mag question

[Orange Boy]

Hi all,
I'm experienced with .380 and .45 ACP reloading, but am just getting my feet wet with .38 Special. In looking over a new Speer reloading manual, a question arose. It's more of a theory question I guess. I thought I would seek the answer here.

I know the .357 Magnum cartridge is made 1/10" inch longer (so that it cannot be chambered in a gun designed only to fire .38 Special)...yet....38 Special can be fired in the .357 Magnum firearm. In looking over the reloading manual for the various bullet/powder combination's for 38 Special/38 Special +P/.357 Magnum I was wondering why someone could not achieve .357 Magnum type ballistics from a cartridge handloaded for a straight .38 Special revolver? Let's assume that the revolver is rated at 38+P. Why not a hotter than +P load with the shorter cartridge length to be chambered in said 38+P gun? I know there must be some good reasons, I'd just like to ask you all to let me know. BTW...I don't plan to do this...just all hypothetical.
Thanks all,
Orange Boy (Bob)

Oh yeah, almost forgot...why do the .38 Special bullets all seem to be .358 diameter and most of the 357 magnums are .357 diameter?????

 

[rcmodel]

At one time the factories loaded the .38/44 cartridge, which for all practical proposes was what you are asking about. It very nearly was a .357 on a .38 case.
They were only intended to be fired in Lg frame guns like the N-Frame S&W, Colt SAA, and Colt New Service revolvers, and the boxes were so marked.

But unfortunately, some folks didn't read the warnings on the box and blew up lighter .38 Spl guns. If they didn't blow up, they very quickly shot loose.
The 38/44 load was discontinued many years ago for that reason.

As for reloading?
.38 Spl brass is not as strong as the old 38/44 brass, or modern .357 brass.

Plus, if you load something known to be of unsafe pressure in little or old .38 Spl guns, how do you propose to maintain tight control over every round from now on?
What if you drop one at the range and somebody else picks it up and shoots it in Grandpa's 100 year old gun?

Normal .357 Mag and .38 Spl bullet diameter is .357" for jacketed bullets, and .358" for lead bullets. They both use the same exact bullet diameters.
Most all of the .38 Spl loads you are looking at must be for lead bullets.

rc

 

[W.E.G.]

This topic comes up here pretty often.

Short version of the answer:
Not all .38 Special brass is created equal.
So, even in the strongest guns, its generally ill-advised to load .38 Special cases to magnum pressures.

I suspect the .38 Special cases marked "+P" can take higher pressures, but I don't have any data to back that up.

Besides, if you are handloading for the .357, and you want to play with pressures, doesn't it make more sense to DOWN-load .357 cases than it does to UP-load .38 cases?

 

[Archie]

Not a good idea.

It's not the case so much as the firearm.

A typical .357 Magnum case may or may not be stronger than a typical .38 Special case; but the rated pressure level for a .38 Special revolver is around 12,000 to 15,000 pressure units while a .357 Magnum is rated for 35,000 pressure units.

Some newer guns may be able to handle higher pressures, and some might not. It is unquestionably not recommended.

Finally, one cannot use .357 Magnum loads in a .38 Special case. The difference in internal volume jacks pressure up considerably.

 

[oneounceload]

a typical .357 magnum case may or may not be stronger than a typical .38 special case; but the rated pressure level for a .38 special revolver is around 12,000 to 15,000 pressure units while a .357 magnum is rated for 35,000 pressure units.

bingo!

 

[NotSoFast]

I would hate to load a .38 spl round with .357 magnum loads then forget and chamber one in a straight .38 spl. That's asking for trouble and there is absolutely no way I'd do it. I'll use .38 spl cases to load up to .38+P but no more.