38Spl load in a 357Mag case? Any danger?

No danger, but you will likely loose a little velocity due to the larger initial volume in the case. There is a lot of data out there you can probably find 357 Magnum data that has velocities the same as you 38 load.

That said I have never understood the aversion to shooting short cases in long chambers. I have shot 1000's of 38 Short Colt in my 627 with no issues. YMMV, no danger shooting 38 Special loads in 357 Mag other than a loss of velocity.

The way to avoid lead build up in your cylinder is to clean your gun. Using 357 cases only puts it more towards the forcing cone.

I shoot more 38sp than 357 because most of my cases are 38sp. Haven't found that the visual "ringing" of the cylinder chambers causes insertion problems with 357 cases - so far..

Is the "ringing" an indication of old lead fouling or is it more an indication of "flame cutting", similar to what sometimes happens to the revolver top strap after being exposed to the flame from the barrel/cylinder gap?

Agree. Scrub out the cylinders and don’t worry.

That being said, there’s lots of light magnum loads out there. So go for it OP.

Some powders can be position sensitive, resulting in lower then normal velocity. Walkalong has some data posted.

I do that all the time. I do add a 0.1-0.2gr to the 38spl load to compensate for the larger case volume.

Walkalong said:

When handloading light .357 loads one does need to keep powder position sensitivity in mind.

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That's what came to my mind as well.
I have not tested it, because I have no aversion to shooting .38 special out of my .357, but if you load .38 data in a .357 case with a powder like Bullseye, that doesn't fill any case, there is a looooooot of extra room in there. I don't know how sensitive it is though.

Add 10% to a 38spcl charge weight when using a .357mag case and you’ll roughly match the same velocity. There are a few Do Not Reduce powders out there where going below starting 38spcl data could be unsafe, and inherently, using that same charge in a larger mag case equally unsafe, but the volume ratio comes out nicely - add 10% when using mag cases.

I hate cylinder rings, and honestly, I hate having excessive numbers of lots of brass, so I’ve been loading reduced loads using special and colt data in mag and Casull cases for many years.

The question comes up often. By doing so you no longer are shooting a 38 special "load" you are shooting a watered down 38 special load. So, as Varminter stated above, increase the charge by 10% to compensate for the larger case.

My favorite 38 Special load is a 158 lead, 3.5 grains Bullseye. Most of the time this clocks about 760 fps out of a four inch barrel, I think this load is a bit slow:





I wanted to develop a load, in 357 cases, that was equivalent in velocity to my standard 38 Special load. Four grains was very close to where I wanted to be, and it shot well enough offhand:






This Colt MKIII must have a tighter barrel as well as a longer barrel, as velocities were just a bit higher:














AA#5 grouped well:







I preferred 158 lead bullets going just at 800 fps in the Colt MKIII, they were less snappy than the faster loads. If you are using Bullseye or Titegroup for your powder, I really, really doubt that using a standard 38 Special load, in a 357 case, will cause any issues. I have seen some very light loads in the 45 ACP with both of these powders, that won't function a 1911, and I think the primary concern with fast powders and too light of charges, is sticking the bullet in the barrel. Which could happen.

Titegroup is not case sensitive.

I found that Clays does not meter very well.

Has anybody loaded WST in the 357 case? I have some 125 SWC that I would like to build a lite load with. Also have considered trail boss in these too. Thoughts?

I think, IIRC, that this was one of the first topics I saw when I started looking at reloading forums, in 2007. The only "danger" would be a bullet stuck in the barrel with a light 38 Special charge in a 357 case. Early in my reloading I researched the difference between 38 and 357, looking at lower loads and figgered unless I used a "target" load, like -3 grains of Bullseye, there would be no problems. I took "normal" loads right out of my manual and dumped them in 357 brass and never a problem. That was in 1975, and no stuck bullets. I do the same with my 44 Magnums; Special data in Magnum brass...

Cleaning the "dreaded" carbon ring out of the cylinders was not my motivation, 'cause I clean my guns after every range trip. I was more curious than anything...

I found an answer to this question from the source - Phillip Sharpe; co-creator of the .357 Magnum.

from... Complete Guide to Handloading by Phillip B. Sharpe (1937)

You are loading far more power than has ever been crammed into a revolver cartridge before, and in so doing you load at your own risk. The Hercules Powder Company and Smith & Wesson refuse to recommend the reloading of this particular number because of these things. It can be done by the careful man, however. But if care was ever needed in the reloading of a revolver cartridge, it most certainly applies to this particular number. The handloader will do much better to use these cases and load standard .38 Special charges.

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Now, that said, .38 special was typically loaded over a wider range (and much hotter) in 1937 than it is today. For reference...

Sharpe: .38 Special 158 gr Factory Lead
Bullseye -- 1.5 gr-4.3 gr
Unique -- 3.5 gr-6.6 gr

Lyman 48: .38 Special .158 gr Cast
Bullseye -- 3.0-3.4 gr
Unique -- 4.0-4.5 gr

It looks that Lyman's .38 Special loads would be included in what he believed to be "Standard .38 Special charges".

Chillydog said:

Has anybody loaded WST in the 357 case? I have some 125 SWC that I would like to build a lite load with. Also have considered trail boss in these too. Thoughts?

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I use it with the 158gr LSWC, 4.1-4.2 gr WST. WST is my favorite powder for soft shooting BE loads in 45acp and 357mag. I very seldom shoot the light bullets.

I was thinking that if I loaded 357Mag cases to 38Spl spc I could avoid the build up in my cylinder from using the 38 rounds. I can't think of any reason this would be dangerous but thought I would ask.

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IMO there is no danger in using any .38 spl load in .357 mag cases except the possibility of sticking a bullet in the barrel if you load lighter than .38 spl start level from any manuals standard loads. I'd be very careful using light cowboy action start loads, making sure they exit the barrel consistently.

I have shot a lot of .38 spl in my .357 magnums and have never had any problems with magnums sticking or being hard to extract due to powder fouling in the chambers because of the the difference in case length however I always clean my guns after shooting. The cylinder cleaned with a single pass through each chamber from either a solvent soaked patch or brush followed by a dry patch. Since I've always had more .38 spl cases and cleaning the cylinder is so quick and easy there seems little reason to use up .357 mag brass for light loads.