.38 Special v. .357 Magnum Casings

[Countryfried Frank]

What is the difference between .38 Special and .357 Magnum outside of case length? Did they beef up the case head area on .357 to handle the higher pressure or just make it a little longer to help prevent accidentally chambering it in the wrong revolver? Also does anyone know the volume of each case?

DISCLAIMER:
I have been reloading for about one year, I have read one handloading manual cover to cover (twice) and read the sections discussing metallic cartridge loading of a second manual. I freely accept any verbal lashing from any reloading troll with the understanding that the aforementioned troll's primary intent is to maintain my ability to count to ten without removing shoes and socks.

[carver952]

http://kwk.us/cases.html .357 Mag volume 27
.38 Special 1.155 in, .357 Magnum is 1.290, 10% more

[JJ]

What is the difference between .38 Special and .357 Magnum outside of case length?

Did they beef up the case head area on .357?

Also does anyone know the volume of each case?

Case Length.

No.

Case volume will vary from manufacturer to manufacturer and from lot to lot. Do you want liquid volume? I could check a coupel when i get home.

[Seismic Sam]

More history: The 357 Mag was made longer specifically so that it will not physically fit in a 38 cylinder. Same for 44 Spl and 44 Mag. The SAAMI pressure for a 38 Special is a very low 17,000 PSI, which is even lower than the 45 ACP. The SAAMI pressure for the 357 Magum is 35,000 PSI, so it's slightly more than DOUBLE the 38 Special. My guess with the 357 Mag is they beefed up the whole EFFEN case!! I will leave it to your own imagination what would happen to you if you put a 357 load in a 38 Special case and fired it in a 38 revolver, which is ALSO much weaker than a 357 Mag revolver.

[rugersol]

if you're considering trying to make hot .38's to shoot in a .357 cylinder, I wouldn't bother ... pressure's gonna be a lot higher, for the same ft/lbs ... and the buildup in the front of the chamber's likely to be greater.

.357 brass is cheap/plentiful and lasts forever!

[Countryfried Frank]

http://kwk.us/cases.html .357 Mag volume 27
.38 Special 1.155 in, .357 Magnum is 1.290, 10% more

Bookmarked. Thanks!

I will leave it to your own imagination what would happen to you if you put a 357 load in a 38 Special case and fired it in a 38 revolver, which is ALSO much weaker than a 357 Mag revolver.

The exact reason I don't own a .38 Special revolver.

if you're considering trying to make hot .38's to shoot in a .357 cylinder, I wouldn't bother ... pressure's gonna be a lot higher, for the same ft/lbs ... and the buildup in the front of the chamber's likely to be greater.

I admit that the thought has crossed my mind but my main reason was to identify the area that I have the greatest 'fudge factor'. I've loaded two .38 Special squibs that I thankfully caught in time. I typically am an err on the side of caution kind of guy but I'm beginning to think that the cautions side is a little more potent in this case. Thanks all for the opinions, info and advice.

[Seismic Sam]

Yeah, if you start messing around with 357 loads in 38 cases, you're going to wind up changing your handle to "H110Fried Frank!!

[Dutch]

Just in case someone gets bored: It would be interesting (for what I don't know ) to take a same brand 357m and 38sp, trim down the 357m to 38sp length and weigh them....

[Countryfried Frank]

Just in case someone gets bored: It would be interesting (for what I don't know ) to take a same brand 357m and 38sp, trim down the 357m to 38sp length and weigh them....

I have Magtechs of each. I'll try that tomorrow.

[Countryfried Frank]

The Mrs. got sick about a third of the way through our movie but I got the chance to play a little sooner once I got everyone else to bed . Sam, you are right. There is more beef on a .357M. I can't say for sure where it is but the .357M I trimmed to .38 length is 8.1 grains heavier than a .38S from the same manufacturer. The .357M brass is nickel plated but the .38S brass is not. I'm not sure how much of a difference that makes but I'm willing to bet that it's small enough that I won't be able to tell with the equipment in my basement. I had a hard time getting consistent volume measurements using water; I had a +/- .5gr spread on multiple measurements so I tried using a powdery material (WP on the spreadsheet) that I have in good supply. In retrospect, a denser, smaller grained powder would probably have been a better choice to showcase the differences in volume but since I was able to get repeatable results (+/-.1gr) with this powder I stuck with it. For each of the measurements I checked three times and recorded the average of all three measurements. If you look at the spreadsheet you will notice that the volume of the .38S case is reported as 22.8 gr/H2O and 7.6 gr/WP untrimmed but 23.2gr/H2O and 7.5 gr/WP trimmed. The .38S case was not trimmed but I did re-measure it when I checked the .357M after trimming. I included this to show that there is a deviation and to give an idea of how much.

To get a baseline I measured the mass and OAL of both cartridges. I then pulled the bullets, measured the mass of the charge, bullet mass and bullet length. After that I turned my attention to the brass. I measured the mass and length then volume both as grains of water (gr/H2O) and grains of powder (gr/WP). After all the baselines I trimmed the .357M brass to 1.149" to match the .38S case length and repeated the measurements on both cases.

I think it is a safe assumption that a Magtech .357M case is not simply a Magtech .38S case stretched at the mouth. Since it had a lesser volume and greater mass when trimmed to the same length as the .38 there is some additional material that was not trimmed away, probably in the area of the case head. I found it most interesting that the volume of the untrimmed .357M was actually closer to a .38S than the volume of the trimmed .357M.

[Dutch]

Awesome..... Now go back and also measure a 38SP +P

[Seismic Sam]

When you have two similar cases, the easiest way to compare is to section them and then polish the edges and remove any burrs, and do a macro photo of both cases standing together. Then you can make any measurement you want with someting like Paint Shop Pro X3 by counting pixels.

And as far as the only difference being the case head thickness, you can forget about that!! A 2x stronger case is going to have different internal dimensions throughout, and there are lots of precendents: The original 44 Automag case was a cut down and inside reamed .308 case, and it's nasty shorter evil twin is the 45-08, which is essentially a 45 Super Dooper (as compared to plain 45 Super) made out of the same .308 cut and reamed brass. Same deal for the 9x23 Winchester, which is 25% heavier than a 9x23 Supercomp. 9x23 Win is essentially a cut and reamed .223 case, which explains why it runs at 52,000 PSI just fine. (Note: 9x23 Winchester is obviously made and drawn from scratch rather than altering .223 cases, but the internal dimensions have to be very close.) 9x23 Supercomp has its roots in the 38 Super, and the original 38 Super had a SAAMI limit of 26,000 PSI and 38 Super +P has a limit of 36,000 PSI. That's still a helluva long way from 52,000 PSI!

I suspect if you pull up the Wiki data for the 38 Special and 357 Mag you can get all the measurements you want.

http://en.wikipedia.org/wiki/.38_Super