Manufacturing question regarding .357 Magnum.

M

Micahweeks

New member
I searched the forum but didn't find an answer to this burning question in my mind. There was a thread asking us all to just name off a (not necessarily realistic) dream gun that we would like to have. Of course, being a fan of the .357 mag, I said my unrealistic dream gun would be a double stack .357 magnum pistol.

Now, I know it is unrealistic because rimmed cartridges are just not a good mix with magazines as they don't feed reliably. But, I was wondering what keep us from being able to take the .357 mag cartridge and just changing the rear to that of an auto cartridge?

I know that someone is thinking of the .357 Sig being the answer to my question, but it isn't. Reloading for the .357 Sig doesn't offer the same versatility as the mag. So, why can't we make a .357 mag with an auto rear?
 
IIRC the Coonan used the regular 357 cartridge. Nothing to keep an enthusiastic and dedicated shooter from making a .357 Auto case-ala the 44
Auto Mag. But that was a commercial failure. Not sure if the Coonan is still in production. The 41 Action Express is another example of an attempt to create
a semiauto counterpart of a revolver round. Didn' t sell. Double stack? Many shooters find the grips of the Browning High Power and S&W M-59/M659 too big for a comfortable grip. Sounds like an interesting idea, but is there really a markey for it?
 
purely from a 'pondering' perspective...very little demand for such a critter (there is the hugely oversized Desert Eagle for those who wish to shoot rimmed magnum cartridges out of a semiauto); tradition is another factor; universal acceptance of caliber and favored platforms to shoot it from is another factor; simply put, it works well and why fix it if it isn't broke?!? :confused:

on the flip side...even though the .357 Sig has made a niche for itself in the firearms market, it too lacks in universal acceptance among shooters when compared to other long standing choices (9mm, 9mm+p, .45 acp, .45 acp+p, and even .40 S&W), meaning factory ammo is more expensive since it is made in smaller batchs, reloading supplies are not as readily stocked for it, and it wears out guns faster than other semiauto calibers
 
Well, I understand what you're both saying, and I know the .41 and .44 auto mag were attempts to create auto counterparts to popular pistol rounds. But, what I wonder is why we made the .357 Sig out of a .40 case? Why couldn't we just take the .357 mag as it is and just change the rear of it? I would figure that the length of the cartridge should not be a problem as many people have no problems with the Glock 20, and the 10mm is as long an auto cartridge as I can think of.

I envision a full-size, polymer frame (maybe the G20/21 frame or the FNP45?) chamber in ".357 auto mag." My dream.

**Clarification**
I know there actually WAS a .357 auto mag, but it was a.357 bullet in a necked down .44 casing. I'm wanting to see it in the .357 mag case.
 
Well, I guess for the same reason we wanted grips wide enough for the 10mm. I don't see grips being much different, but I could be wrong. I'm just holding up a 10mm cartridge next to a .357 and not seeing any reason that the grip wouldn't be just as manageable for both.
 
I'm guessing it would be 'firearm sacrilege' to lop off the 357 lip and make it an auto cartridge. Too many wheelgun purists.
 
What you're talking about would roughly be the .357 analog of the .44 Automag. What was done there was to find a rimless rifle cartridge that was the proper base/body diameter and cut it down to the length required.

You wouldn't need the same length case used by the .357Mag, but even with a shorter case the cartridge is going to make the grip size very large in a double-stack magazine design.

The 9x25 Dillon might satisfy your desire to experiment using readily available components, dies & firearms.
 
The question is not whether or not it could be done, but why? One of the biggest advantages of the .357 Magnum is its versatility. You would lose much of that versatility by putting it in a semi-auto which is going to be way more sensitive to pressure, bullet type, and overall cartridge length.

For instance, try shooting a soft shooting wadcutter cartridge in a .357 semi-auto. It may not have enough pressure to operate the action, would be too short, and certainly would have feeding problems even if it wasn't too short.

And all of the above aside, it really is too long of a cartridge for a double-stack pistol. The 10mm auto is a long semi-auto cartridge, but the .357 Magnum is considerably longer than the 10mm auto.

The only real advantage to a .357 semi-auto is to get the power of the .357 magnum which can be done with existing semi-auto cartridges in smaller guns than would be necessary for the double-stack .357.
 
I wondered how big the ejection port would have to be on a pistol trying to eject .357 mag. Huge.

Well, ok. So it is just impractical to put a .357 mag in an auto. Is there an alternative cartridge that you can get the same power, speed, and versatility out of that is more readily available than 9x25?
 
10mm is very similar in performance to the .357Mag. Other than the obvious bullet diameter difference, just about any other performance metric you choose will have them neck & neck.
 
Really? I was always told that the hottest 10mm loads still didn't quite match the .357 mags best 125 grain load. Where can I find the load info your talking about for the 10mm?


*Giddy! I already have a 10mm! Gotta get the stuff to reload for it, though, if it can match .357.*
 
It's hard to compare apples to apples because 125gr is not a common bullet weight for the 10mm, but most ammunition manufacturers provide their velocity numbers online if you want to try to do comparisons.

You have to be a little careful because some manufacturers seem to load hotter than others--especially in the case of the 10mm. It's best to do comparisons by looking at multiple loads from a single manufacturer rather than trying to compare across different manufacturers.

Double Tap loads a 125gr JHP .357Mag load that provides 1600fps from a 4" revolver.

DoubleTap sells a load that will push a 135gr bullet to 1600fps from a Glock 20.

Here are some results from an ammo survey I did a few years ago.
attachment.php

attachment.php
 
So tell me if I got this right. According to those charts, the 10mm outperforms the .357 in terms of power rating in the heaviest loads while the .357 categorically outperforms the 10mm in terms of energy?

If that is right, in layman's terms, what does it mean to me? Does it mean that one hits harder or stops quicker? What's the difference in power and energy?
 
Ok. I was able to do a little more research today on my original question, and I was able to figure out the logistical problems of putting an auto rim on the .357 mag cartridge. But, what I was reading did help me come up with a couple of more questions.

The .357 SIG supposedly mimics the performance of one particular .357 Mag load very well, but it lacks the versatility of the .357 Mag for reloading. So, since the .357 Sig and .40 S&W use the same size case, wouldn't the .357 Sig also have the same size case as the 10mm? Could we give the .357 Sig a longer, 10mm size casing to allow for more versatility?
 
My understanding of why law enforcement always liked the 357 Mag is that it penetrates through car windshields and other rounds do not. Does anyone know if the 357 Sig, the 40 caliber, and/or the 10 mm penetrate car windshields? Other than the Secret Service and Sky Marshalls, does anyone even use the 357 Sig anymore? I think most LE services are using either the 9 mm or the 40 cal.
 
Uh, it's been done, pretty much.
Winchester brought out the 9mm Winchester Magnum along with the .45 Winchester Magnum for the Wildey pistols. I don't think they ever made a gun for the 9mm W.M. but one of the late tipping barrel so-called Automags might have been.

Long before was the 9mm Mauser "Export" which was well up into light bullet .357 magnum country.

Readily available? No.
 
If that is right, in layman's terms, what does it mean to me?
Click to expand...
In layman's terms it's splitting hairs. :D

The bottom line is that if you pick any common factory loading of the .357Mag you can safely exceed its performance in the 10mm with similar weight bullets.

If you look at the offerings from smaller ammo companies who specialize in wringing every last bit of velocity/performance out of a given caliber then the .357Mag appears to enjoy a small velocity advantage with lighter bullets while the 10mm might have a small velocity advantage with heavier bullets.
...does anyone even use the 357 Sig anymore?
Click to expand...
The TX state troopers use it. I believe the Dallas PD does as well. It's not going to threaten the .40 or 9mm in LE holsters, but it's not going away either.
Could we give the .357 Sig a longer, 10mm size casing to allow for more versatility?
Click to expand...
You're talking about the 9x25 Dillon.
 
You must log in or register to reply here.
Back
Top