.38 special psi vs. .357 magnum psi

[Pagel93]

I have been reloading pistol ammunition for a few years now, and I know I will never understand it all.

Something I noticed when loading .38 special the average PSI is approximately 15,000, with a maximum level of approximately 17,000.
Yet, .357 magnum PSI is between 29,000 to 39,000. I understand there is the difference in powder and case length causing the different pressures.

But if a pistol chambered in .357 magnum and is capable of handling the pressure. Is there a reason to not load .38 special to higher pressures.

 

[Recoil45]

The main problem is where do you find data to do so? Case volume from the 38 to 357 is very different. Using 357 data to load a 38 case will result in a very dangerous load level.




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[robertc1024]

One of the points of developing the .357 Mag was that it was longer so it wouldn't fit in a gun designed for .38 spl. I couldn't find any information on the brass thickness being different so I suspect IF you could keep the pressure levels at .357 levels, it would probably be fine in a .357 Mag revolver. I wouldn't go there though because somewhere down the road when you've got a new .38 spl revolver, and you find a random round on the back of the shelf loaded to those levels, you will have a big problem.

 

[Pagel93]

Thank you for the reply.
This is where I must show my ignorance or limited knowledge of this field.How much effect does the case length have on the actual load?
I know between a .357 magnum and a .38 special there is about 3.43 millimeters difference in length. To the best of my knowledge the deeper the projectile is to the powder, so a shorter case length, would cause a larger build of of pressure leading to a higher PSI. To me, I understand this as loading a .357 magnum with 3.5 grains of powder would have a lower PSI than a .38 special with the same powder, and vice-versa.

Correct me if I am wrong in this matter.

 

[Younggun]

Reducing internal volume will increase pressure, assuming all other variables remain the same.


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[oldag]

And there you have it.

 

[Younggun]

To the original question: I have found differences in brass thickness between 38spc and .357, but the cyclinder takes the brunt of the pressure.

Loading .38spc to .357 pressures will be extremely dangerous to fire on a .38spc handgun, will be identical in appearance to properly loaded .38spc, and in the best case scenario will likely result in stretched primer pockets and overworked brass.

You also will not have any guide to reaching those pressures. Using .357 load data will likely result in much higher pressure than intended due to the reduced volume of the .38spc case.


All in all, it's a terrible idea.


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[ROGER4314]

True confessions here..................
It was 1966 or 67, and I was so broke as a college student in Kansas, that I did use .38 special brass with magnum loads. I loaded the magnum loads in that brass because I couldn't afford anything else and didn't know better. They were fired in a Ruger Blackhawk revolver with 4 5/8" barrel and I never had a cartridge failure of any kind. If you're familiar with that pistol, you'll note that the cylinder is massive and built like a tank!

My experience suggests that the extended length of .357 magnum brass is largely to prevent chambering the hot loads in an older or weaker gun.

Having aired the dirty laundry here, lets talk about the down side of loading smoking hot loads in 38 Special brass:
When I finished with that pistol after several years of ignorant reloading mistakes, the barrel was shot to Hell and rounds from it key holed at 50 feet. I trashed a great gun!

Any of those reloads in the wrong hands, could turn the shooter's prized .38 Special S&W Model 36 or Banker Special into a grenade.

I would have been legally responsible if anyone was inured due to my dangerous reloading practices.

It would have been tough to live with knowing that I disabled or blinded an unsuspecting shooter.

Please don't consider using low pressure cartridges brass for magnum loads. It's a bad deal all 'round and very dangerous.

The Internet didn't exist then. Today, we have the ability to contact experienced reloaders in just moments. Use that to your advantage.

It was a good thread. Thanks for posting it!

Flash

 

[Pagel93]

Again, thank you to everyone that took the time to answer my question. While I had no intentions of attempting to push the limits, due to a deep affection for my revolver and my fingers, it was a why not question that had been bugging me that for once google was no help on.
In essence it comes down to the limited case volume and more importantly the lack of data to safely over charge the round, without possibly blowing out your brass or worse your cylinder.

 

[Dawico]

There is no real reason to load 38 Special to hotter loads. Even +P loads are questionable if you own guns that can't handle them.

If you want Magnum loads then use 357 Magnum cases.

I just don't see any good coming from it.

 

[robertc1024]

Using .357 load data will likely result in much higher pressure than intended due to the reduced volume of the .38spc case.
All in all, it's a terrible idea.
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I wholeheartedly agree with the second statement, but the first begs a question. I have read that you can get secondary pressure spikes if you have too little powder in a large volume too. Can anybody confirm that?

 

[Younggun]

It's about detonation.

It's the reason you have to be careful what type of powder you use downloading .308 to subsonic. .50 BMG requires specially modified cases to load subsonic rounds or (less perfect solution) using fillers mixed with the powder to reduce the volume.


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[Dawico]

I wholeheartedly agree with the second statement, but the first begs a question. I have read that you can get secondary pressure spikes if you have too little powder in a large volume too. Can anybody confirm that?

If the powder is laying in the bottom of the case below the flash hole you can have issues.

It can not only cause a squib, the primer can start the bullet before the powder goes off causing a strange spike in pressure.

 

[Bowyer]

Loading 38 special to 357mag specs is a bad idea for this reason. It still looks like a 38 special and could be accidentally loaded into a 38 special revolver and cause a catastrophic failure.

I didn't read all of the other posts so if I have repeated this info then I'm sorry.


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