View Full Version : 357 Sig or 9mm +P Is There Any Real Difference ?

Mike H
March 25, 2000, 03:56 PM
Does the 357 Sig really offer much over a good quality 9mm +P JHP round. I know that the 357 Sig pushes a 125gr bullet faster even than a 9mm +P, but isn't the bullet size practically identical ?

You lose capacity with the 357 Sig because of its larger cartridge, and the blast and recoil are MUCH worse than a 9mm +P. am I missing the point here, the cons seem to outweigh the pros. Also is there any actual shooting evidence to support the assertion that the 357 Sig is THE must have round as I believe that several police forces are now using this caliber and so one would expect some actual performance data/anecdotes.


Mike H

March 25, 2000, 05:56 PM
i'll start off by saying my 2 favorite pistol rounds are the .357sig and the 9mm. then i'll say that i like the .357sig more than the 9mm. i like it more because it is a better defense round with more stopping power. i mostly have 9mms since its cheaper for target practice but i plan to get a .357sig soon. i would also like to say that i feel the 9mm is a very good round and i would not feel undergunned if i had to carry it.

now let me try to explain the advantages of the .357sig over the 9mm.

the .357sig performs very differently than the 9mm +P. the 9mm +P is designed to penetrate LESS than regular 9mm, deliver all the shock imediatly and expand very quickly. for example Federal 9BPLE (a 115gr +P+ 9mm) is designed to only penetrate about 10 inches and do extreem damage to those 10 inches. many people don't like rounds like this since they say it doesn't penetrate enough but it has a VERY good street record.

the .357sig is designed to deliver most of its shock quite fast and expand quickly but it also is supposed to penetrate more than 9mm+P. most .357sig 125gr bullets penetrate about 15 inches. IMHO these are great balistics and thats why i like it. it works somewhat like a 9mm+P yet penetrates alot more; by that i mean it expands just as much if not more as quickly but doesn't underpenetrate. also other advantages to the .357sig is its great barrier penetration. the .357sig is designed to penetrate just about anything (windsheilds, plywood, heavy clothing) and still penetrate and expand well. this is due to its hyper velocities and large HP cavity. since the .357sig is a bottlenecked round it will still feed reliably with an even bigger HP cavity than the 9mm.....and as you were saying the 2 bullets aren't practically the same size the bullets ARE the same size. both are .355 caliber.

and as for the cons you mentioned in most guns the bullet loss is only about 1-3 rounds which isn't much.
as to what you said about blast and recoil being "MUCH" bigger IMO your wrong about this. the only .357sig i have shot was a sig 239, now thats a sub compact gun and i could control it very easily. the recoil was quite compareable to that of a hot 9mm and, ok i'll admit it is a loud round but that can be at an advantage also. if your in a shoot out and the BG hears a huge BANG then he might be more likely to run away.

I believe that right now there are about 4 or more state police who carry the .357sig along with the secret service and the FBI. One of the first to switch was the Texas DPS. they have only had a couple shootings and as far as i know they were very pleased with the results. in all cases i have hear the BG stopped whatever he was doing, fell and never got up.

as i said i would feel quite well armed with either a 9mm or a .357sig
in 9mm i would feel safe with any of the following grains in order for home defense use:
115gr +P/+P+
124gr +P/+P+
however for carrying i would chose them in possibly this order:
124gr +P
115gr +P+
in no situation would i feel safe with a 9mm 147gr.

as for .357sig the only load i like is the 125gr

my 2 favorite loads are federal hydra-shocks and speer gold dots. as for the 115gr +P+ 9mm i like federal 9BPLE

to rap this all up 9mm and .357sig are both great defense loads but i would take the .357sig over any 9mm load.

the .357sig does definetly have a substantial difference in performance over the 9mm. i would take the .357sig over the .45 even in most cases especially due to its high likelyhood of actually expanding like its supposed to.

[This message has been edited by Russell92 (edited March 25, 2000).]

March 25, 2000, 06:14 PM
also i forgot to mention that the .357sig is a very accurate round. i shot the sig 239 extreemly accurately with little effort. this due to sig's accurate guns and that the .357sig is an accuarate round with a flat trajectory.

as to what i was saying about .45 it has had so many failures to have the HP open up that i am fed up with it for a carry round. i still feel it's the best home defense round but i just wouldn't trust it for carrying. i hear many stories where a .45 JHP turns into a FMJ when it doesn't expand and the BG is barely stunned by it.

March 25, 2000, 06:26 PM
357 SIG emulates 357 Magnum when using 125gJHP's.

To do the same in 9mm requires over-SAAMI ammo (hot hot hot!).

"All my ammo is factory ammo"

March 25, 2000, 08:41 PM
Good luck finding actual performance data. The round has not been in service long enough to compile an extensive amount of data.
That said, I know of a few DPS shootings that produced OSS with the .357 SIG. Texas
DPS adopted .357 SIG after conducting tests where they found the .357 SIG emulated the .357 Magnum. They used their statistics for .357 Mag. to determine that the .357 SIG will deliver the same stopping record.

Mike H
March 27, 2000, 04:58 PM
Thanks for the replies guys.

I have noticed that a LOT of people have invested in a Sig P239 in .357 Sig for their carry weapon, usually with those Hogue finger groove grips. My local gun store says that people are trading in their 9's for .357 Sig whereas just 6 months ago it was almost always for the .40 S&W. I'll say one thing though, FMJ practice ammo. is VERY expensive, I'll stay with my 9mm Rem. UMC fodder until I get a pay rise.


Mike H

Glock Raider
March 27, 2000, 06:54 PM
Mike H the price of the .357 practice ammo is dropping as more companies are beggining to manufacture the round. Hang in there and the price will be competitive with the others soon.

Rainbow Six
March 27, 2000, 07:06 PM
I get Atlanta Arms 124gr FPTCJ .357SIG practice ammo for $12 a box (50 count). It shoots good and is fairly accurate. I don't know if they have a website but here's the addy off the box for those of you that can't find reasonably priced .357SIG practice stuff. The phone # is from information, I haven't tried it. If it is incorrect, let me know and I'll try to get a good one.

Atlanta Arms & Ammo, Inc.
721 Vine Circle
Social Circle, GA 30025
Phone#: (770)464-2203

March 27, 2000, 10:22 PM
Glock Raider is right about the cost of the .357sig. Bought 8 boxes this weekend at $8 for a box of 50(speer). Saw winchester at $10 a box, and many folks are selling reloads in the $12-14 for 100 bags. .40SW is also dropping as it gets more popular.

March 28, 2000, 08:14 AM
The 357 SIG is faster than the 9mm from the same barrel lengths. Consider it a 9mm +P++?
That isn't really fair, since some 9mm ammo actualy operates at higher pressures than the 357 SIG (some NATO/+P+ 9mm is loaded to 42K psi; the 357 SIG maxes at 40K psi).

It does generate more energy than the 9mm. If that really makes any difference, or how much difference, is open to debate.

As far as expansion and penetration, the different 357 loads are all over the place (from 9-16 inches, moderate expansion to fragmentation). According th FBI tests, the 124 Speer Gold Dot 9mm +P expands more in bare gel (.68 v .60), about the same after cloth (.53 v .54). The 9mm penetrates a little less in bare gel (13.4 v 16), a liitle more after cloth (20 v 19).

Some much slower 9mm loads penetrate and/or expand as well/better than the 357 SIG too. So do some 40/45 loads. The Fed 38 Special 147 HS +P+ and 40S&W 165 HS go at least 12 inches in all the FBI tests 100% of the time to the Fed 357 SIGs 92.5%. Most other 40/45 loads do that or better too. Avg exp for the 9mm is about the same, the 40/45 a little more.

It is not "Excaliber". It is pretty good. Might be better for you, might not.

I like it; got six pistols that shoot it.

Another good choice, not conclusively the best? Another way to skin the cat, not necessarily a better, or best, way for everybody all the time?


March 28, 2000, 03:28 PM
I like the 357 SIG better than the .40 because it has less torque and can be a little faster at followup shots for me.

I also like the 357SIG because it's cheaper to reload with the little 9mm bullets. And it's easier to find my brass since not that many people shoot this caliber, at least yet.

The 357SIG is also amazingly flexible. I can download it to be very mellow just like a standard 9mm luger round, or I can really kick magnum butt with it.

As long as you have a magazine that works well with the 357SIG, it's a piece of cake to ram a 9mm bullet into a 10mm chamber. I like that.

The 357SIG bottlenecked cartridge is also more efficient than a straight walled cartridge, based on Accurate Arms Ammo Company, and my own testing. Standard deviation can easily be around 5 fps. On a bad day with some powders it can get as high a 22 fps, which is also quite reasonable.

Now that bullet ballistics has improved so much, it is no longer necessary to follow the century old standard of getting the biggest, fatest bullet possible (in a straight walled case) in order to stop a bad guy. So people are starting to see the benefit of the efficient bottlnecked pistol (little rifle) cartridges.

Mike H
March 29, 2000, 12:51 PM
I would have to agree about the efficiency of the .357 Sig even when compared to the .45.

I have just got through reading an old small arms booklet that stated the high velocity round fired by the .30 Mauser in the world wars was identified by ground troops as the most feared handgun round. They commented that its high velocity caused wounds to be "all chewed up" where other bullets just punched a relatively neat hole. It is for this reason that I'm a fan of this round, in 115 or 125 grain loadings it really moves that 9mm slug along.

Mike H