357 Recipe In Shortened 357 Case, How Much Pressure Increase?

[arakboss]

If I shortened a 357mag case to a 38spl case length and loaded a 357mag recipe in that shortened case, how much pressure increase (as a percentage) would I likely see?

Read More

 

[DizzyJ]

What you mean is if you load a 38SPL case with a 357 charge.

 

[arakboss]

What you mean is if you load a 38SPL case with a 357 charge.

Essentially but using a 357 case that has been trimmed down to 38spl length. They may have different internal dimensions that change capacity, thicker web for example.

 

[Joe13]

I don't reload but understand how most of it works.

My question is why would you want to do this other then boredom.

It sounds like you want a really hot 357 - I would think a full size case would be better suited to that.

Let me know what I'm missing…

 

[arakboss]

I don't reload but understand how most of it works.

My question is why would you want to do this other then boredom.

It sounds like you want a really hot 357 - I would think a full size case would be better suited to that.

Let me know what I'm missing…

Boredom is as good of a reason as any.


I would like to know approximately how much I would have to reduce a charge from a 357mag recipe, to get safe 357mag pressure in a shortened case. A person could enter in a 357mag recipe in a 38spl case with a reloading program but that would not account for different internal case capacities. Maybe those differences are small enough not to matter?

 

[Reloader762]

Some year ago I was give more 38 special cases than I could ever wear out shooting. Having several 357 Magnum handguns and being a caster of bullets for the last forty years, I knew exactly what I was going to do with those case, turn them into Skeeter Loads https://americanhandgunner.com/discover/the-lyman-358156-bullet/

I have two original Lyman #358156 SWC molds as well as a NOE clone of the mold in a HP version. Pre Powder Coat days, 357 Mag. with traditional lube on the left set up for 357 Magnum loads and recovered 38 +P bullet tumble lubed with 45/45 /10 with gas check left off on the right shot from a S & W 2" snubby. Alloy used was 50% pure lead and 50% of my COWWs with a pinch of tin.



Bullets can be loaded to almost identical length in 38 Special cases using the lower crimp groove. This also allows you to load light to med. 357 mag loads in 38 Special cases in a pinch if you find it necessary to do so.


Original Lyman #358156 SWC powder coated and ready to gas check.

 

[arakboss]

My original question would apply to using 10mm cases shortened to 40 S&W length, 460 Roland case shortened to 45acp length, etc.

 

[orygun]

Since 38 Special cases are much easier to come by than 357 Magnum cases, this is the first question that @arakboss has posed that I think is nutz. Personally, I think it's a huge waste of time and resources. I doubt there is any real benefit to using a shortened Mag case over a Special case.
But weighing the shortened 357 case compared to a 38 Special case would be a good place to start.
One could start with +P 38 Special loads and work up, but there's not going to be a good way to tell when the pressures have gotten out of hand.

Maybe a Powley Computer would be a good purchase?

edit; I'd trade 2 38 Special cases for each 357 Mag case...

 

[NeoBlackdog]

If you still have fingers to type with after doing this experiment be sure and let us know how it turns out.

 

[arakboss]

If you still have fingers to type with after doing this experiment be sure and let us know how it turns out.

If necessary, I will use speech to text and let you know either way

 

[Papercidal]

The two cases are identical except in length the .357 mag is only lengthened to prevent it being chambered in a .38 spec gun.

 

[arakboss]

The two cases are identical except in length the .357 mag is only lengthened to prevent it being chambered in a .38 spec gun.

How does it handle more than 50% higher pressure?

 

[NeoBlackdog]

How does it handle more than 50% higher pressure?

That's probably more a function of the chamber construction of the firearm than the actual brass.

 

[orygun]

How does it handle more than 50% higher pressure?

That's probably more a function of the chamber construction of the firearm than the actual brass.

I believe this is correct, but now I am wanting to cut a couple of cases apart and see if the Magnum case does indeed have thicker walls and web.

 

[arakboss]

I believe this is correct, but now I am wanting to cut a couple of cases apart and see if the Magnum case does indeed have thicker walls and web.

It sure looks like they do in this photo.

 

[orygun]

It sure looks like they do in this photo.


View attachment 1902214

Yes, it does. But the picture also shows some weird bullets, so who knows?

 

[2Wheels4Ever]

Honestly, I've been loading .357mag in .38sp cases for over a decade. Zero issues.

 

[arakboss]

Honestly, I've been loading .357mag in .38sp cases for over a decade. Zero issues.

That will make my experiments a lot easier.

 

[arakboss]

Honestly, I've been loading .357mag in .38sp cases for over a decade. Zero issues.

Do you use full book loads or down load them a tad?

 

[NeoBlackdog]

Do you use full book loads or down load them a tad?

And what happens when someone accidentally puts one of those higher pressure rounds in a revolver chambered/designed for .38 Special?