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Article The .357 SIG

By Overkill338, Jan 30, 2017 | Updated: Jan 30, 2017 | | |
  1. Overkill338
    The .357 SIG wasn't the first bottleneck handgun cartridge. In the 1960's Winchester necked the .357 Magnum down to to .257.Then the 9x25 Dillon came along in 1988 by necking the 10mm Auto down to .355". Finally in 1994, SIG Sauer and Federal with a joint venture, shorterned and necked down the 10mm to create the .357 SIG. Some think you can form it using .40 S&W brass, but the .40 is 0.009" shorter than the .357 SIG.


    The idea of this cartridge was to try to match the 1450 feet per second 125 grain .357 Magnum, which is #1 in 1 shot stops in history. In a 4" barrel service pistol the Speer 125 grain Gold Dot .357 SIG is advertised at 1350 feet per second. Federal HST 125 grain 1360 feet per second. These two listed loads are two of the best we have to use in .357 SIG and I would feel confident with either, but Im a long Gold Dot fan. In chronograph comparisons I was able to find, you get 3%-4% more velocity when using a 4.5" Glock 31.

    357 2.png

    While it is not EXACTLY a .357 Mag, the .357 SIG has proven itself to be a very capable cartridge. Its very effective at barrier penetration (windshields,car doors, etc). Several Police Agencies have adopted it. The Virginia and North Carolina State Police, and even our local Sheriff's departments. As its popularity has risen with LEA's, its also became more popular as a personal defense caliber. Recoil is very comparable to a .40 S&W, just not as snappy. I'd take the .357 SIG over a .40 any time. Id also carry Underwood Ammo's 125 grain Gold Dot, thats advertised at 1475 fps and 604 ft/lbs, which gives you an amazing proven bullet at the original 357 Mag speed. They also offer a 147 grain XTP at 1250fps & 510 ft/lbs.

    If you have not tried the .357 SIG, you really should. For us Glockaphiles, its as easy as a barrel from Lonewolf and your 22/23/27 can be a 31/32/33 no magazine change needed. Also the 10mm Glocks can be converted to .357 SIG with just a barrel, but the 10mm can also be a 9x25 which Im considering for my own G29 if I can find a bullet that can hold up to the speeds.

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  1. mikeh1
    "Overview of the .357 SIG cartridge"
    Nice overview! Cleared some mis-information I had in my head since myP239 purchase in 1999! BTW, it always has gawkers at the range...something about the "report" that everyone has to ask "what is that?".
    Cheers, here's to another 18 years of happy .357 SIG shooting.
  2. Awan
    "Good Information"
    Thanks for this article. I have been contemplating purchasing the G32 and this article may have sold me. Hickcok45 has a couple of videos on the G32 and the interchangeability of the G23 .40 barrel and mags. I believe I would rather purchase the G32, then buy a .40 barrel, rather than buy the G23 and buy a .357 SIG barrel. The cost of the ammo is a little higher, but not THAT much more.
  3. DubfromGA
    "Great info"
    interesting read

    I've wanted a .357 Sig for a while now and this may have been what temps me to go ahead.

    It'd make for a decent woods gun possibly, as well.

    I'll look around at possible 40 cal offerings and see if a .357 barrel doesn't find its way, too.


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  1. TexasRaider
    Let me add, it's my understanding the Illinois State Police thought so much of the .357 Mag that when they went to the S&W m39 9mm in the late 60's, they essentially told Federal to make the 9mm into the 125 gr. SJHP .357 Mag and the +P+ 9BPLE was born. I don't know if the ISP collected specific shooting data back then, but anecdotal evidence and street word was everywhere in the 70's that that round flat *worked*.

    Just because they didn't have the recording requirements of today doesn't mean the perception of those historical rounds is wrong or the testimony of those police shooters discarded simply because it can't be measured by today's standards. That's like saying every murder conviction that occurred before DNA testing came along must be thrown out and the prisoner freed because that conviction can't stand up to today's testing capabilities.

    Whether we believe the .357 Mag is the best manstopping round of all time is a matter of opinion, almost faith. Even by today's standards, one must believe in a specific grading system before a round can be graded. If you believe the FBI's current protocol is right, then the current crop of 9mm's are the best we can carry. But if the FBI is wrong, better rounds exist elsewhere. And if no definitive standard for current loadings exists today, how can we call into doubt what apparently worked so well for numerous Troopers, Deputies and Officers so many years ago?

    It comes down to this; Do we believe those old guys when they say they used it, it worked superbly, was a stellar manstopper and they trusted it? Because in the end, that's all we really have from those days. I for one believe them and think the 125 gr. 357 Mag is the best overall handgun round a person can carry. But it's a 6 shot revolver round. The next best thing? The .357 Sig, about 93% of .357 Mag with a capacity twice that of the revolver. But again, it's a matter of opinion bordering on faith.

    Good article!
      Poohgyrr likes this.
  2. TexasRaider
    Proving the .357 Magnum was the number one 'one shot' stopper of all time is problematic not only due to the innumerable number of variables at play in a gunfight (was the guy coked up, was he in poor health, was the shot dead center in the heart, was it a shoulder hit, was it from a few feet or 50 yards, et cetera), but I think the biggest issue with proving that is that during the time the 125 gr. SJHP .357 Mag did rule the streets, it was when no real databases for police shooting widely existed, nor was the practice of cataloging the specific types of loadings widely conducted. I wish we could jump into Mr. Peabody's Wayback Machine and record those events from the late 60's up to the early 90's (when my dept finally moved away from the S&W m28 and on to Sig pistols), it would probably be eye opening or at least serve to confirm or debunk some current theories.

    However 'unreliable' and anecdotal the evidence is however, it is there and shouldn't be disregarded. Just as many a GI may have exaggerated the power of the 1911 .45 ACP ("a real wrist-breaker!"), the truth is that word of mouth and anecdotal evidence is correct that it was far, far superior to the FMJ 9mm of the same time period. When talking to the old grey beards that carried the .357 Mag in that famous loading, especially the ones who were in shootings or the Rangers who investigated those shootings, it's clear that if the shooter did his job and put the round in or darn near the A Zone, the perp would nearly always go down, and NOW. It was a tremendously powerful round, and no other police round had the trust, word of mouth or street cred that that round did in those days.
      Poohgyrr likes this.
  3. Railsplitter
    With the Underwood Ammo 125 gr Gold Dot you get about 100 fps more velocity than the 357 Magnum and a superior GD bullet. This round in a G31 4.5 inch barrel easily outclasses the traditional 357 Magnum round for round and has 10 more rounds to spare.
  4. jeremiahjj
    I've seen ballistic reports from DoubleTap, etc., and the .357 Sig caliber with the 125-gr. projective beats 'em all in both velocity and energy. High ammo price is the only objection.
  5. wganz
    You missed the .38-40, the original forty, as a necked down .44-40.
      Overkill338 likes this.
    1. Overkill338
      I mentioned the 38-40 in my 10mm Auto article but forgot it here.
  6. StLJohn
    Another good article both interesting and informative. Been thinking of getting the .357 Sig as an addition to my stable of autoloaders, and will start by converting my G22. Depending upon how that goes, maybe a 33 or 27 conversion?
  7. TheDreadnought
    You need to cite your sources.

    You claim .357 Mag is #1 for 1 shot stops in history. Is this just your opinion? If not, cite your source. If you don't have a source, you probably shouldn't present it as fact.
      RACHIGER likes this.
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    2. my_old_glock
    3. TheDreadnought
      That's a WIDELY disputed report.
    4. StLJohn
      So the expectation is to cite sources whenever something is stated as fact? Is this for just articles, or this blog in general. I haven't seen that standard applied consistently anywhere or at anytime in GT.
  8. my_old_glock
    If you reload, you can resize 357 Magnum bullets down to size using a LEE push-thru sizer (0.356). I have used several different types of 357 Magnum bullets in my 9mm guns without problems. The only one I found that didn't work/feed in my G26/17 was the Speer 135gr GD HP SB bullet (#4014) because the nose was too large, but it should work in a bottle-neck cartridge - although I see no reason for using a Short-Barrel/Low-Velocity bullet at high velocities. I have used Hornady 140gr XTP (#35740) bullets with no problems. I have not gel tested any of those bullets, but they should behave the same as they do from a 357 Magnum cartridge of the same velocity.

    FMJ will always hold up at high velocities.

      StLJohn and Overkill338 like this.
    1. Overkill338
      Thanks for the reply, I'm just an amateur writer.