Brass difference: .38 SPL vs. .38 SPL + P

mtbore

mtbore

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Was sorting through a new batch of .357 Magnum brass today. As usual, there is the occasional .38 Special that sneaks in. I put them aside and maybe I'll load a batch some day.

Anyways, this time, a lot of the little guys are headstamped "38 SPL + P". Normally I just find "38 SPL". Now I know what a +P load is all about. But can someone confirm what I thought I knew to be true... that a 38 SPL +P load is perfectly safe in a 38 SPL case (when fired from a +P or .357 Mag gun, of course)?

I'm guessing the headstamp is just for factory load labelling. The brass itself (Federal nickel plated in this case) looks identical. I calipered a sampling and the +P wall thickness is in the 0.0095" to 0.0115" range, same as 38 SPL.
 
+P is a piece of jargon.It refers to a slightly souped up .38 spl.
treat it like a .38 spl.It is not a .357 mag.The cartridge case itself may be built slightly stronger than the .38 spl,but it refers more to the gun in which the +P was meant to be fired,than to the case.Hope this makes sense.
 
+P or +P+ means more powerful charge in the cartridge. Case may or may not be thicker and I'd inspect it more careful before reloading.
 
i would just think it is a higher pressure load and would be less inclined to use that brass, and would inspect it more carefully than normal loads
 
AFAIK

A 38 SPL +P load is perfectly safe in a 38 SPL case (when fired from a +P or .357 Mag gun, of course)

The head stamp is just for factory load labeling
 
At the mouth of the case you won't see a diffrence between the cases. I think if you section each case diagonally, you may find that the +P is thicker at the case web. Measuring at the mouth of the case, it would be the same.
Therefore, with the same amount of powder, you'd have less room in the +P case, but increased pressure.

Or were those 9x23 cases I sectioned and measured some time ago comparing to the case web of a 9x19.

Easy to chop up some cases to be sure, I guess.
 
"...a 38 SPL +P load is perfectly safe in a 38 SPL case (when fired from a +P or .357 Mag gun, of course)?..." Yep. +P cases are the same as any other case. The +P means it was loaded to a higher pressure than normal.
 
+P cases are identical to regular 38 spl cases. The only difference is the headstamp.

From the Starline Brass website

38 SPL+P has no difference from the standard 38 SPL, other than headstamp designation for load segregation. Due to standard case design, will handle +P pressures with no problems.
Click to expand...

There is very little difference in pressure between a 38spl and +P load. Both are very low pressure.

 
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You might be interested to know that the very first .357 mag was actually a .38 special case loaded very hot and marked .38-44. After someone probably blew up some .38 special revolvers, the case was lengthed so that it could not fit into a .38 special chamber and there is were the .357 mag came from.
Then some smart guy came up with .357 max....

Scott
 
Walking encyclopedias, all of you. Thanks for clearing that up.

Seems pretty obvious that gun construction is what improved the most (and needed to) since the blackpowder era. .38 Special brass cases in 1902 might have been up to a .357 Magnum load today but the guns weren't.

Not that I'm going to do this... just a crazy thought experiment... Does anyone think seating a bullet just 0.135" higher in a .38 Special case might effectively allow .357 Magnum loads with similar safety confidence as if they were in a .357 Magnum case (which is just 0.135" longer, after all). I recognize one difference would be that the bullet would be unsupported for its final 0.135" of travel out of the case, so there would be some more gas escaping early and thus less bullet velocity... Crazy talk, but maybe helpful to understand what's happening.
 
357 loads in a 38spl case not a good idea. The pressure for a 38 is 17000 psi and 35000psi for a 357, if someone ever got ahold of one of your special 38s loaded to 357 mag and put it in the wrong gun unknowingly, poof!
I wouldn't risk it!
 
tigrr said:
357 loads in a 38spl case not a good idea. The pressure for a 38 is 17000 psi and 35000psi for a 357, if someone ever got ahold of one of your special 38s loaded to 357 mag and put it in the wrong gun unknowingly, poof!
I wouldn't risk it!
Click to expand...

If a gun can't chamber a proper .357 Mag round then it shouldn't chamber what I'm describing either. Same C.O.L. as .357 Mag, just in a .38 Special case.

Of course I agree... the "38 SPL" headstamp would be misleading. Same potential confusion with wildcat loads and their headstamps, I guess.

I have no reason to ever try this. Plenty of .357 Mag brass right now. BUT... if the world comes to an end and I've worn out all my .357 Mag brass and I'm staring at a shiny pile of .38 Special brass... ;)
 
mtbore said:
If a gun can't chamber a proper .357 Mag round then it shouldn't chamber what I'm describing either. Same C.O.L. as .357 Mag, just in a .38 Special case.
Click to expand...

Not sure about that... in revolvers, if the rim doesn't catch on the cylinder face, the cartridge headspaces on the case mouth, not the tip of the bullet. Case length, and not C.O.L., determines where the cartridge stops.
 
Cerdan said:
Not sure about that... in revolvers, if the rim doesn't catch on the cylinder face, the cartridge headspaces on the case mouth, not the tip of the bullet. Case length, and not C.O.L., determines where the cartridge stops.
Click to expand...

Maybe I misunderstand what you're describing, but how could a .38 Special or .357 Magnum rim not catch on the cylinder face? They're a rimmed cartridge. (And roll crimped.)
 
Take revolvers chambered in rimless, semi-auto cases, for example 10mmAuto. Use of moon clips is recommended for ease of extraction, but if you chamber'em without moon clips, the cartridges don't pop out the back end 'cause they're rimless, they abut against a shoulder inside the chamber.

Same goes for .38/.357. I used to think that .357mag cases couldn't chamber in .38spl revolvers 'cause the COL was longer and they'd stick out the back end of the cylinder, but in fact, the case mouth stops against a shoulder in the chamber before the rim hits the cylinder face.

In the example you gave, even if the COL of your modified .38spl is the same as a .357, there' s a good chance it'll still chamber in a .38spl revolver, because the length of the case, and not of the loaded cartridge, determines headspace.
 
mtbore,
what you are describing is what happened when the .357 magnum was first invented. I may be wrong but I believe it was Elmer Keith who first loaded .38's to magnum velocity with the bullet seated out further, before Smith & Wesson commercialized the idea and Winchester came out with a new longer case. Some Lyman "Keith style" cast bullets are designed to seat at either of two crimp grooves. Such a long-seated bullet in a .38 case would protrude from the front of the cylinder in many light .38 revolvers, and would render the revolver non-functional. But it could fire in some others.
I was thinking of loading cheap .38 brass ".357 style" to shoot in my Rossi 92. I think the strong action would handle them no problem. But it is somewhat uncharted territory.
 
Cerdan said:
Same goes for .38/.357. I used to think that .357mag cases couldn't chamber in .38spl revolvers 'cause the COL was longer and they'd stick out the back end of the cylinder, but in fact, the case mouth stops against a shoulder in the chamber before the rim hits the cylinder face.
Click to expand...

Interesting. I know my .357 Mag chambers have shoulders and I assumed they were mostly there to start to "guide" the bullet before it enters the forcing cone. (And to gather crud.) But sure, I suppose that could function as a stop for a bullet... Thanks!

And thanks, Longwalker. So I'm just reinventing some history with my unoriginal idea? Not surprising. It's reassuring that it has been done before and probably could safely be done in a pinch. (Especially since I have no .38 Special guns to worry about mixing up ammo with.) I love the range of the .357 Magnum cartridge so it would take a serious brass shortage before I'd consider a high-seated bullet load in the .38 Special cases... :)
 
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