.38 Special VS .357 Magnum

[Lavid2002]

We all know there is a HUGE difference between these two from the factory....but what difference is there to a reloader?

Surely .38's should be loaded more conservatively if they will be shot out of a .38 wheel gun rather than a .357.

But how can someone tell? When I work up reload I just watch the primers and casings for excessive pressure.

I'm sure 99% of reloaders dont have a CUP tester, so how do we know when to stop for a .38, and when to reach a .357's max. potential?

Thanks : )

-Dave

 

[flyguy958]

You have pushed too far when they call you "three finger" Dave.

Start with book loads and stay within the max listed, of course after working up to that.

 

[Sevens]

Yeah, I don't tend to write my own loads. I use published loads as my guideline.

There are no published loads that are close between .38 Special and .357 Mag unless you are reading balls-to-the-wall .38 data and comparing it to swaged lead bullet cowboy action loads for .357 Magnum.

Nowhere close.

 

[Lavid2002]

but what if a starting load for .357 mag flattens out the primers? It just doesnt seem legitimate that the same primer can be a warning sign for a .38 and a .357....


Of course, I wasnt taking the max .38 book loads into consideration
Thanks...sometimes I skip over the obvious...

 

[FEG]

Surely .38's should be loaded more conservatively if they will be shot out of a .38 wheel gun rather than a .357.

At the risk of sounding pedantic, .38 Special should be loaded according to .38 Special data. .38 Special +P should be loaded according to .38 Special +P data. .357 Magnum should be loaded according to .357 Magnum data.

In other words, a revolver rated for .38 Special +P can handle +P loads, etc.

Loading higher-pressure cartridges in .38 Special cases with the intent of only shooting them in a .357 Magnum is a really bad idea. The case itself is a limiting factor.

but what if a starting load for .357 mag flattens out the primers? It just doesnt seem legitimate that the same primer can be a warning sign for a .38 and a .357

The primer is not operating in isolation. Primer signs reflect the amount of powder, as well. Think about it: the same small primer is also used for both .25 ACP and 9mm Para.

A flattened primer is not necessarily a sign of high pressure, absent some other pressure sign. A lot of Federal .357 factory loads will also show a slightly falttened primer, in my experience.

 

[joneb]

but what if a starting load for .357 mag flattens out the primers?

When I first tried AA#9 for .357 mag. using 158gr JHPs and CCI 500, I had flattened cratered primers and sticky shell extraction with starting loads. Well starting data per some and 1gr grain under starting for another, I upped the charge and the pressure signs were gone. I'm not saying this is a solution for your situation, just food for thought. I have worked up loads near Max. per one manual and found them to be the starting load in another
Error on the side of caution.

 

[Lavid2002]

The primer is not operating in isolation. Primer signs reflect the amount of powder, as well. Think about it: the same small primer is also used for both .25 ACP and 9mm Para.

I know they reflect the amount of powder, and pressure....which is why I am saying

If the .38 SPL can be loaded to 18,000 PSI (Guessing I forget the exact amount) and you are supposed to back off when the primers start to flatten how is that even legitimate when I can load an identical casing (Just 1/10" longer) with an identical primer, but just a little more powder and still use the same thickness primer cup to watch my pressure. But I can go all the way to some 35,000 PSI

 

[FEG]

If the .38 SPL can be loaded to 18,000 PSI (Guessing I forget the exact amount) and you are supposed to back off when the primers start to flatten how is that even legitimate when I can load an identical casing (Just 1/10" longer) with an identical primer, but just a little more powder and still use the same thickness primer cup to watch my pressure. But I can go all the way to some 35,000 PSI

A casing that is "just" 1/10" longer is not identical. It makes a BIG difference. Furthermore, the difference is actually 0.14," or a slightly bigger difference. The .357 Magnum case has a thicker body and web, which also affects the pressure signs.

 

[Jim243]

Lavid2002

You are pull our leg, right? I am not sure how you got to 2,377 posts without knowing the difference between a 357 mag and a 38 spl. And no, it is not a little powder difference or even the same type of powder. Or the same type of case OR that the revolvers are remotely the same, they are not, except that they both have triggers and hammers.

So you are pulling our leg, I just want to know if it is the right or left leg?

Jim

 

[FEG]

So you are pulling our leg, I just want to know if it is the right or left leg?

Some of the members have been on my case a little lately for being too blunt. Thanks for saying what I really wanted to say.

Just in case you are not pulling our legs, pressure is a function of the cartridge/gun combination. Every variable you can conceive affects pressure signs. SAAMI specifications are an absolute maximum that attempts to eliminate all possible variables.

 

[SL1]

Livid2002 wrote

It just doesnt seem legitimate that the same primer can be a warning sign for a .38 and a .357

BINGO!!! It CAN'T!

There is a lot of silly advice about "working-up loads and looking for pressure signs" for cartridges that have such low SAAMI pressure limits that there should be NO pressure signs before the pressure limit is GREATLY exceeded. I think that type of generic advice misleads a lot of new reloaders.

Also, there are a lot of lists of pressure signs that SEEM to indicate that they are applicable to ALL guns and cartridges. But, that simply isn't true.

It is always wise to stay below the max loads in published data that has been pressure tested. Doing that AND being aware of what signs of excess pressure look like FOR THE TYPE OF GUN AND CARTRIDGE THAT YOU ARE USING is the safest thing that you can do without using pressure-testing equipment, yourself. Simply adding powder until you see "signs of excess pressure" can quite easily blow-up guns designed for low-pressure cartridges like the .38 Special, because the FIRST sign of excess pressure in a WEAK gun is often the failure of the gun, itself. It takes a STRONG gun to handle the pressures that will fail a primer or a cartridge case.

The OP has actually hit on a good point for all of us to consider when giving advice to new reloaders.

 

[Lavid2002]

Lavid2002

You are pull our leg, right? I am not sure how you got to 2,377 posts without knowing the difference between a 357 mag and a 38 spl. And no, it is not a little powder difference or even the same type of powder. Or the same type of case OR that the revolvers are remotely the same, they are not, except that they both have triggers and hammers.

So you are pulling our leg, I just want to know if it is the right or left leg?

Jim

Lol!
No no...let me explain...
I wasnt asking the difference between a .38 and .357 I know the difference.
I was asking how can reloaders watch for excessive pressure signs between the two... let me explain...


For the whole time I have been reloading this has been implanted in my brain
*Always work up a load from the suggested starting load, and watch for pressure signs.

Well, since most reloaders dont have a CU pressure tester how can we watch for excessive pressure? Watch for primers flattening, maybe slivers of the headstamp being shaved away from the brass being pushed back into the ejector pin on auto loaders(This is irrelevant since we are talking about a revolver cartridge)...Anyways.

When watching for pressure signs, we reloaders have few tools. One of which is the thickness of the primer cup. When it flattens out we know we are getting hot. Well this same "tool" is used to judge a 18,000 PSI load, AND a 35,000 PSI load....Thats like using a meat thermometer for melting stainless steel.

So my initial question is, how can we watch for excessive pressures for two totally different cartridges when our testing equipment remains the same. Here are my answers
*Max. Loads for the .38 are listed in the books
*This is the best thus far, the EXACT answer I was looking for

BINGO!!! It CAN'T!

There is a lot of silly advice about "working-up loads and looking for pressure signs" for cartridges that have such low SAAMI pressure limits that there should be NO pressure signs before the pressure limit is GREATLY exceeded. I think that type of generic advice misleads a lot of new reloaders.

Also, there are a lot of lists of pressure signs that SEEM to indicate that they are applicable to ALL guns and cartridges. But, that simply isn't true.

It is always wise to stay below the max loads in published data that has been pressure tested. Doing that AND being aware of what signs of excess pressure look like FOR THE TYPE OF GUN AND CARTRIDGE THAT YOU ARE USING is the safest thing that you can do without using pressure-testing equipment, yourself. Simply adding powder until you see "signs of excess pressure" can quite easily blow-up guns designed for low-pressure cartridges like the .38 Special, because the FIRST sign of excess pressure in a WEAK gun is often the failure of the gun, itself. It takes a STRONG gun to handle the pressures that will fail a primer or a cartridge case.

Thanks : )

-Dave

 

[BigJimP]

I understand what you're asking, I think ?? ....and I understand some of those old axioms were out there about "watching for flattened primers", etc as you work up your loads ....but I always thought to experiment like that was a little insane ....

and I don't know if it helps or not ...but I do use the same bullet and the same powder and the same small pistol primers for both .38 spl and .357 mag ...( in different cases of course ) - I only load .357 mag in cases stamped as .357 mag ....- and the powder drops varies a lot of course between the 2 different calibers.

For both I load:
158gr Montana Gold 158gr CMJ bullet
CCI small pistol primers

for both calibers, I load Hodgdon TiteGroup:
for .38 spl I load 3.7gr in a .38 spl case (manuals show 750fps / 15,900 CUP )
for .357 mag I load 5.7gr in a .357 mag stamped case (manuals show 1,200 fps / 41,900 CUP)

Most of the time I'm shooting my reloads(in either caliber) in an N frame model 27 or 28 / maybe a K frame S&W model 19 or 66 .... and only occassionally will I shoot an old K frame Victory model .38 spl I've had for a long time ....and once in a while in a new Henry Big Boy rifle I've recently bought that is chambered in .38spl / .357 mag ....

maybe I'm just a chicken ....but I just don't experiment beyond the published mins and maximums in the manuals... I've never cut a case in half on a .38 spl vs a .357 mag and really looked at the thickness of the brass, differences in the base, etc ...and it may vary by headstamp as well ...I don't know. I just would not trust those old axioms ...

 

[Jim Watson]

identical casing (Just 1/10" longer)

I am concerned that people are discussing the subject who think that is so.

A serious student of the subject would go in and research the .38-44 Heavy Duty revolver and its ammunition. And perhaps read the writings of Elmer Keith and Skeeter Skelton. But they should also check the article concluding that current production 2400 is "faster" than the powder that they had to work with.

 

[Lavid2002]

Stop nit picking at my words, im sure you understand my general question

 

[Jim243]

BigJim

I am sure you do not use the same CASE for 357 mag and 38 spl. That is what Lavid2002 if talking about (357 Mag cases), or at least I think he is.

What he will find out using 357 Mag cases for 38 spl loads, is that he will have extreem over preasure loads (extreem is subjective). Because of the extra space in the case, it will take a bit longer for full pressure to come up and push the bullet out the case mouth and into the forcing cone of the revolver. This pressure spike will result in higher pressures in the case and not burn the powder in the barrel as normal. He will see flattened primers and cracked brass cases by doing this. Is it safe? That will depend on how well the gun was built and how old it is. Should he do it? NO, No, no.

Can he do it?? I would just use a light 357 Mag load instead.

That's just how I feel about it,

Jim

 

[BigJimP]

No, I don't use the same case for .38 spl and .357 mag .... ( I use .38 spl stamped cases for .38 spl ......and .357 mag stamped cases for .357 mag ...) I use the same bullet and same primers ( in different cases ) - for both loads ...but I load .38spl to a different spec than I do .357 mag ...(per the manuals)..

( I must have really mis-read what he meant ) ...but I thought he was trying to use some of "the old axioms" to evaluate the pressure of his loads ...by evaluating the conditon of his fired primers, etc - which I tried to say, I think is a bad idea ! ( because different cases, etc may be a big factor ) ...

I'm confused now about what he's trying to do / and whether I muddied the water even more ?? ..... I added some clarifying notes to my original post ...

 

[Jim243]

I'm sure 99% of reloaders dont have a CUP tester, so how do we know when to stop for a .38, and when to reach a .357's max. potential?

Maybe I miss read his post as well, but why would there be any confusion on what a Max load for 38 spl would be for a 38 spl case? And why would there be a confusion as to a Max load for 357 Mag case?? Unless you were trying to load a 357 mag load in a 38 spl case or a 38 spl load in a 357 mag case.

I don't know, I am as confused as you are now.

Jim

 

[Lavid2002]

Ok...lets clarify

I know the two casings are not the same. The question about using both for the same purpose is not whats up for debate


Whats up for debate is a combination of questions...allow me to word it like this

Q:I am reloading .38 special. How do I know when I have reached max loads and need to stop loading.

Answer, well good sir, watch for sticky casings, and flattened primers. Also, dont exceed the max pressure in the book

Q:I am reloading .357 mag. How do I know when I have reached the full potential of my cartridge and gun?

Answer, Well good sir, watch for flattened, cratered, or punctured primers, do not exceed mag loads in the book.

Thanks for the help hypothetical man in my hypothetical conversation...


BUT WAIT!

*Guys, this is where this question comes into play. I dont wana blow your minds....lol*

It doesnt make sense that a primer that can tell me when to stop loading for a .357 that can go up to 35,000 PSI can also tell me when to stop loading for a .38 special that is limited to 18,000 PSI.

Hence our question, how do I know when I cannot load .38 specials any hotter, and how do I know when I cannot load .357 mags any hotter, yet still reach their full potential.


Note:The answers have already been given and received in this thread. This post was merely to clarify all the confusion about the original question : )

_Dave

 

[Jim243]

Just to clarify the question as to how, it is my understanding that the primer is pushed back out of the case an instant sooner than the case is, when fired in high pressure loads and the force of the case slamming against the bolt face (or slide) flattens the primer back into the primer pocket.

So if you have a high pressure load in 9mm or 38 special or 357 mag or 45 ACP or any other caliber the results are the same.

High pressure spikes can be caused by too much powder or too little powder in the approprate case for caliber. Or by using the wrong OAL and setting the bullet too deep into a case.

yet still reach their full potential

As to full potential, that is a loaded question (pun intended). It will really depend on the quailty, age and condition of the fire arm used if it would handle the full potential of the SAAMI max for PSIs or CUPs.

The best way to measure for yourself is to use a Chrony and measure your FPS (feet per second) against the published data for the powder/bullet combination you are using and see how close your are to the published data.

But you knew that before you posted your question, I guess it's my right leg that feels a bit longer.

Jim