.38 special brass loaded to .357 mag over all length and pressure

Longwalker

Longwalker

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I have a bunch of Lyman cast bullets that are designed to fit .38 special brass when seated to the lower crimp groove, so they are at .357 magnum length. "#358156, 158 grain gas check" I believe. I have data that shows loading them with the same charges as .357 magnum. I've loaded and shot quite a few with no issues.
So that got me wondering. I have a lot of .38 special cases, not many .357 mag cases, and another bullet on hand that has two crimp grooves. The Hornady 180gr. fp/sil. Does anyone have experience or data crimping this one in the lower crimp groove when loaded in .38 special cases and using .357 mag data?
As far as I can see, the construction of .38 special brass is identical in case head thickness to .357 magnum. Or is this incorrect? Depend on brand? It would seem to me that the 1/10" case length is irrelevant if the interior volume/over all length & seating depth is the same.
I'd be shooting these in two strong rifles, not a revolver. Miroku manufactured Win M92 .357 mag and a Ruger M77/357. The Winchester won't reliably feed shorter cartridges.
What do you say?
 
Not because it’s done that it is smart to do so. As long that those rounds cannot find their way in a revolver that cannot handle your over pressure load, it’s you face and limbs after all.
.357 case are made to handle the extra pressure. Not so for the .38 special.
As stated in that link..if you want a .357 load use a .357 case.
 
The difference between .38 and .357 brass is the length and markings. The specific parts of your question, I dunno. I would say it's fine with development, like everything. I have been using .38 brass to load .357 level ammunition for many years. The people who created the .357 did not have anything but .38 brass to work with...
 
Are you not concerned with so little contact with the case the remaining bullets might "walk" out of the case by the recoil?

What powder are you using? win296/h110 needs high pressure to ignite properly.

Just buy some 357 brass is what I would do. Maybe just load some of your brass to +P for now and wait until you have found some 357 brass?
 
Most 38 special loads have pressures below 20,000 units, where many 357 are higher than 30,000


357 brass is easy to find, why bother messing with the incorrect brass?
 
legi0n said:
don't have any info about that 180 gr bullet but loading 357 in 38 spl case has been done before
I load 200gr hardcast for revolver in them 38's but then again I don't crimp cases, I just go for the max length that fits the gun

https://thefiringline.com/forums/showthread.php?t=301800
Click to expand...

Thanks for that link. It is useful to read, but mostly to help me realize that many posters participating in a discussion really don't understand the question. Mine is a somewhat different question about a different bullet and premise.
to Simplify, I am asking about two things:

1. Can anyone point to actual construction differences in .38 special cases in the head area vs. the same brand in .357 magnum?

2. Has anyone seen published data of the Hornady 38/357 caliber 180 grain JTC-SIL bullet loaded long in .38 cases and crimped in the lower crimp groove?

To put some concerns expressed here to rest:

1. I understand the relationship between internal volume & bullet seating depth and pressure. I am NOT asking about seating bullets to .38 Special Over all length but using .357 magnum powder charges. That is well known to result in dangerously high pressures. I intend to maintain the same internal volume as published .357 magnum loads, in shorter cases crimped at the lower crimp groove.

2. I do not own any .38 special firearms. Nobody I shoot with owns any .38 special firearms. Any ammunition loaded in this manner would be labeled "for .357 magnum ONLY". The longer over all length would normally not allow these cartridges to be loaded into a .38 special firearm.

Before proceeding any further or experimenting with this question I intend to compare several brands of .38 and .357 mag brass, trim the .357 mag to .38 length and weigh. I'm pretty sure that will tell me if the .357 magnum has thicker base construction or not.
 
Longwalker said:
Thanks for that link. It is useful to read, but mostly to help me realize that many posters participating in a discussion really don't understand the question. Mine is a somewhat different question about a different bullet and premise.
to Simplify, I am asking about two things:

1. Can anyone point to actual construction differences in .38 special cases in the head area vs. the same brand in .357 magnum?

2. Has anyone seen published data of the Hornady 38/357 caliber 180 grain JTC-SIL bullet loaded long in .38 cases and crimped in the lower crimp groove?

To put some concerns expressed here to rest:

1. I understand the relationship between internal volume & bullet seating depth and pressure. I am NOT asking about seating bullets to .38 Special Over all length but using .357 magnum powder charges. That is well known to result in dangerously high pressures. I intend to maintain the same internal volume as published .357 magnum loads, in shorter cases crimped at the lower crimp groove.

2. I do not own any .38 special firearms. Nobody I shoot with owns any .38 special firearms. Any ammunition loaded in this manner would be labeled "for .357 magnum ONLY". The longer over all length would normally not allow these cartridges to be loaded into a .38 special firearm.

Before proceeding any further or experimenting with this question I intend to compare several brands of .38 and .357 mag brass, trim the .357 mag to .38 length and weigh. I'm pretty sure that will tell me if the .357 magnum has thicker base construction or not.
Click to expand...

Basically the same as B in post #4, but more words.

I've done exactly what you're wondering here, and lived to tell the tale. I've done it in Ruger revolvers and a Handi rifle, labeled them as 38/357, and colored the primer with marker in the event cartridges got mixed up. It wouldn't have mattered anyways, as bullets sit out an extra 1/10" or something, so they look like an odd duck anyways. AFAIC, the cartridge and the firearm are not sentient beings as some seem to think, and internal case capacity is all that matters (with a little bit of unknown voodoo regarding bullet pull/tension). I'd be interested to see the results of case sectioning, but I believe they will show the same thickness.
 
OK, I got the weights, and learned something.... weighed 5 cases of each type, then trimmed the .357 magnum cases to .38 special length.

Federal .38: 66.0 grains avg.
Federal .357: 75.3 grains avg.
Fed. .357 trimmed: 72.0 grains avg. - 9% heavier than .38

Remington .38: 65.3 grains avg.
Remington .357: 76.9 grains avg.
Rem. .357 trimmed: 74.0 grains avg. - 13% heavier than .38

Winchester .38: 63.1 grains avg.
Winchester .357: 78.7 grains avg.
Win. .357 trimmed: 75.7 grains avg. - 20% heavier than .38

So, I learned something.
Case weight, and therefore amount of brass and probably strength, actually do vary between .38 special and .357 magnum brass of the same manufacturer.

Seems that I have part of my answer. but there are two opposing variables in this comparison.
I'm not sure how internal capacity of heavier brass affects pressure. I know in rifle brass, lighter and thinner cases can sometimes handle heavier charges because of more internal volume, but for now I'm going to assume thicker = stronger.

I won't load the same maximum charge of powder under bullets "seated long" in .38 special cases as I will in regular .357 magnum cases.

But I will continue on with my experiment.
Seems like I should be able to develop a long OAL .38 load that will feed in my Winchester M92, be safe, and shoot with a similar sight setting as full .357 magnum loads. I just won't flirt with "full maximum" .357 pressure recipes.
 
from SAAMI
38 spl
LoXAnz0.png


357 mag
TTgTATZ.png
 
Back in the metallic silhouette days it was somewhat common to shorten .357mag brass to .38 special length so the 180 grain silhouette bullet and the 200 grain cast rifle bullets could be loaded to an overall, length that worked in Smith and Wesson revolver cylinders.
What you are proposing to do with the 38 special cases should be fine if you keep the internal volume the same.
 
More data to ponder...

I sectioned one each .38 & .357 magnum case, Fed,Win, Rem. Base thickness was measured with my calipers, alongside the flash hole, front to back. My technique is not precise, because of the slight internal taper on the case bases, but may tell us something useful.
Cases vary in construction between manufacturers.
It appears both Remington and Winchester .38's are built a little thinner than their .357's, but Federal cases have approximately the same base thickness.

Federal: .38 Spec. .186" vs. .357 mag. .188" ( same)

Winchester: .38 Spec. .170" vs. .357 mag. .203" ( +19%)

Remington: .38 Spec. .157" vs. .357 mag. .178" ( +13%)
 

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I load 38 special for when I go shooting with a buddy where I bring my own ammo and shoot as much as I like with his firearms. Is there any markings on brass cases that indicate +P for heavier loads or are they the same brass?
 
legi0n said:
they are the same brass
look at the SAAMI drawings I posted above.
Click to expand...

All of his .38 brass measures thicker than SAAMI .357 spec, leaves me wondering what and why he or anyone is even worrying about at this point...

He found some manufacturing differences which is to be expected, that is exactly why load development is necessary. It's really a pretty benign practice otherwise. I haven't had an issue across at least a dozen guns and tens of thousands of rounds...
 
fiddler said:
I load 38 special for when I go shooting with a buddy where I bring my own ammo and shoot as much as I like with his firearms. Is there any markings on brass cases that indicate +P for heavier loads or are they the same brass?
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