With Sig Sauer’s new line of self-defense ammo just hitting the market, I thought now would be an appropriate time to take a look back at Sig’s last major impact on the ammo industry: the .357 Sig.

First introduced in 1994, the debut of the .357 Sig caliber trailed the initial production of .40 S&W by four years. Twenty years later, .40 S&W is in a comfortable spot as one of the top three most popular centerfire handgun calibers in the country and .357 Sig lags far behind, with no signs of it catching up.

Stranger things have been known to happen in this industry, so I won’t make any bold proclamations about this cartridge having no hope of ever displacing one of the “big three”, but let’s just say things aren’t looking too good for .357 Sig. If it didn’t gain mainstream popularity in 20 years, the chances of it suddenly being embraced by civilians and law enforcement are slim.

cartridge comparison
Left to right: 9mm, .357 Sig, .40 S&W. The .357 Sig uses a .40 S&W case necked-down to use a 9mm diameter projectile.

So what happened? It’s not as if .357 Sig was some wildcat cartridge developed in a garage and sold in sketchy classifieds in the back pages of gun rags. Sig is a major firearms company with a lot of smart people working behind the scenes and a plethora of resources. Shortly after the .357 Sig’s release, a few major state-level law enforcement agencies thought the round had enough promise to adopt it for all of their officer’s duty weapons. Reviews of its performance were mostly positive, but it still failed to catch on. So why not?

I don’t claim to have it all figured out, but there are a few contributing factors that seem pretty obvious:

  1. Almost all new handgun cartridges fail to catch on. The market for rifle cartridges is a little different, but for handguns, it’s almost impossible to start from scratch and get a new cartridge to catch on. The most popular handgun calibers are almost all 100 years old, and the top two (9mm and .45 ACP) have been used by our own military, boosting both their popularity and availability. The newest handgun cartridge that could be considered mainstream is .40 S&W, and I don’t think the market could handle more than one exception to the rule in such a short time period. So from the very start, it was an uphill battle for the .357 Sig.
  2. When a new handgun cartridge does “make it big”, its success can almost always be tied back to its adoption by law enforcement. That seems to have been Sig’s goal from the beginning, and they did see some success. But they were up against the giant Glock marketing machine, which was in its prime in the 1990s. Glock not only convinced scores of police departments to switch from their beloved All-American steel and wood revolvers to Glock’s new fangled plastic space Euro-guns, they also went back to those same departments a few years later and got them to all upgrade those 9mm Glocks to .40 S&W versions at virtually no additional cost. This is what Sig was up against in the effort to attract business from law enforcement, and it’s no wonder they came up short.
  3. I think marketing and hype have a lot more to do with a cartridge’s success than its actual performance, but it certainly helps if you can demonstrate some performance gains when putting together that marketing strategy. The ballistics for .357 Sig are certainly not bad by any stretch, but they’re not appreciably better than .40 S&W, either. Recoil is very similar, capacity is the same, and the size of the guns is identical. In order to prove some advantage over .40 S&W, you’d have to point to velocity or muzzle energy numbers, which most people have no idea how to interpret, or somehow demonstrate its ballistics performance, probably with gelatin tests. If that’s the best thing you have in your marketing toolbox for your new round, you’re gonna have a bad time.
  4. New calibers are out and new bullets are in. The last twenty years have seen huge leaps in terms of expanding bullet technology. Today’s bullets penetrate farther and expand more reliably than what was on the market when both .40 S&W and .357 Sig were introduced. A 9mm today can do what a .40 S&W did twenty years ago, and while there is still some gap between today’s 9mm and today’s .40 S&W or .357 Sig, that gap is a lot narrower, and 9mm will always have an edge in capacity and recoil. Those who insist on more “power” are probably better served by bumping up to a .45 ACP. Police departments and government agencies are slowly transitioning from their “intermediate” handgun calibers back to 9mm as a result. Unless something really crazy-groundbreaking is developed, I suspect future advances in handgun technology will focus on new bullets, which is a lot more practical and economical for the end user than switching to a new caliber.
Sig P226
With a simple barrel swap, many pistols can be converted from .40 S&W to .357 Sig vice versa. Most even use the same magazines for both calibers as well.

I have no doubt that some agencies and individuals will continue to stand by .357 Sig for many years, and they will probably be well-served by the cartridge. It’s a good caliber with a solid reputation and performance history. Pistols using the cartridge might need more frequent spring replacement, but otherwise, they should continue to work as well as any other guns. As an added benefit, converting these guns to .40 S&W, and even 9mm, is usually incredibly easy and affordable. But I really doubt we’ll see many new pistols in this caliber any time soon (other than perhaps from Sig Sauer), and ammo is unlikely to be as prevalent as the other popular calibers.

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  • Paul Hamilton

    Enjoyed his type of articles informative and well written.

  • Stewart Fowler

    I still enjoy the parent case in my Glock 20…. I mean if your going to go, go all the way…10mm auto baby!

    • James V Feragola

      I agree, picked up a G29sf a few years ago. By far my favorite round to shoot.

    • Nate Opgenorth

      Ever try 9×25 Dillion? Instead of a necked down .40S&W shooting a 9mm bullet its a necked down 10mm Auto shooting a 9mm bullet and its velocities and power are pretty epic.

  • Richard Gregor

    I thought the .357sig would be cool to own so i bought a glock 32 when it was on sale, thankfully the .40 barrel was cheap enough…
    The sig is nice, but as they say its trying to fill a gap that isn’t there

  • Charlie Morris

    Interesting i almost bought a 357sig but i realized it was not the 357 magnum i favor lol thanks for the info i always wondered about that caliber

  • Ron Newkirk

    This round was made by a specific company for a specific handgun. Too much out of the main stream. Not versatile enough. Too few guns were around that could utilize this round.

    • Berry Holleman

      catch this

  • Mark Mullineaux

    I loved the 357sig and shot hundreds of thousands of rounds through it competitively. Then they lowered the definition of Major to something obtainable with 9mm and I went with the higher round count.

    • Glenn Eric Johnson

      2 rounds isn’t much of a difference

    • Mark Mullineaux

      With a 6 1/2 inch barrel, 357sig was giving me a power factor of 225. A comp brought it to very little recoil. Still I went with the lower power factor and higher round count.

    • Glenn Eric Johnson

      Mark Mullineaux the round count advantage is marginal at best, cost and availability wise, 9mm is better, but terminal ballistics, 357 sig is king, especially underwood, double tap, corbon, and buffalo bore.

    • Mark Mullineaux

      I have a Glock 24 with a drop in comp barrel. My biggest problem was getting springs light enough to operate the 9 mm major with no felt recoil.

    • Glenn Eric Johnson

      Mark Mullineaux glock 24?

  • Melvin Carney


  • Mark Sullivan

    I bought a P229 Sig in .357 Sig to add to my collection, I don’t shoot it often but enjoy it when I do.

  • John Mahoney

    Ive read about this round for a while now and its muzzle energy and velocity surpass that of .40 SW,but all in all it still just punches a 9 mm hole and ammo availability is still hit or miss,at least in my neck off the woods.

    • clcntx

      A 38 S&W, 38 Special, and 357 magnum all punch the same size hole.

  • Anwar Azo

    I LOVE THE GUN 40 SW & 357 SIG .

  • Trav Sienknecht

    Just picked up a .357 Sig P239. Love it! Hard to find ammo locally, but Lucky Gunner hooked me up.

    • Scotty J.

      That’s my choice of carry weapons. It’s a great concealable weapon that fires an outstanding round.

      • Tom F

        I use the p239 SAS.All edges smoothed,action job and DAO,love it

  • Roy Cook

    I’ve bought a .357 bel for a model 23 and 27 glocks.
    The energy with a .40 135 grain and a .357 sig. .124 grain are so close I find it hard to prefer one over the other so I go with ammo availability and swap brls as needed.

  • Lindsay McGeorge

    I own a Glock 31 w/adjustable sites. I replaced the stock non ported Glock barrel with an aftermarket extended and compensated barrel. Along w/ a 3 1/2 lb disconnector accuracy and follow up shots are vastly improved. Snappier than a 9mm with as fast, shot to shot placement on target. And yes, 40 cal of course work just fine. Muzzle flip is now tame. Before the flip was close to the violence of my 686 S&W .357 magnum. Now close to hot 9 mm rounds.

  • Roy Scott

    secret service uses these

  • Jack Reid

    Loved it. Info is good, reliable info is priceless

  • Oliver Harris

    I understand that the Secret Service, which is the bodygard for high federal officials, use the .357 Sig for its penetration in case the assailant is wearing thick clothing or body armor. But can’t confirm. Love the P226 and have a barrel for .357.Sig, 9mm and 40 S&W. My shooting club does not want me to use the .357 Sig on their 3/8″ steel sihlouette targets. That tells me something. Also we can’t use our 10mms

    • Glenn Eric Johnson

      their main purpose is investigating fraud

    • Charlie Simons

      Protecting detail used fn57s in 5.7×28.

    • JPGurgs

      I’ve used Underwood 10mm 135 gr Noslers in my Glock 20SF, and directly compared them to Underwood 357 SIG 125 gr Gold Dot loads using a KKM 10mm to 357 SIG conversion barrel. The flash and blast of these two particular loads out of my G20 are very similar, with recoil from the 10mm 135 gr Nosler being slightly greater. The 10mm load while 10 gr heavier is a lot faster and yields a lot more energy than the 357 SIG load out of my G20. The issue is ammo availability and high cost. All things considered, I prefer the versitility of the 10mm over the 357 SIG. IMO the 10mm offers more versitility than 9mm, 40 S&W, and 45 ACP as well.

      • srsanbo

        A larger case and bullet will offer you all that. If cost and weight are not major factors, 10mm is an attractive option. You can load light and have a round similar to .40 in performance and shootability, or go heavy and have .41 magnum energy. I opted to go .357 Sig because I have a G17 already, and can reuse my holster(s), mag pouches…and it was a pretty decent price as an LE trade. A G20 would be a great addition to the safe, however.

    • David Doucette

      Lol. I’ve shot 3/8″ steel silhouettes at 50 yards with my 357SIG. It folds them into a taco.

      • http://www.luckygunner.com/lounge LG Chris

        I love tacos.

  • Oliver Harris

    Guys, look in Cartridges of the World. You will see that the .357 Sig has twice the muzzle energy of the other two cartridges. That’s because of higher velocity and velocity is squared in the formula for muzzle energy. Don’t know what you guys have been reading.

    • David Doucette

      In fact, the 357SIG has as much energy at 100 yards as a 9MM does at the muzzle. It’s also flatter shooting (bullet trajectory). Bullet drop out of my P229s short barrel is only 1.2 inches at 100 yards!

  • Patrick Slevin

    I think the author is right. The future might see the 9mm and 45acp once again competing for business while the 40 and 357 SIG ride off into the sunset. It’s too bad as I think the 357 SIG has the most going for it. It’s a ballistic giant. Ever run any of these rounds across a chrono? I’ve never seen SD and shot to shot differences so close. Veloctiy for the reloader can be kept around 1400-1500 ft/sec depending on barrel length and that’s equal to a 4″ 357 mag round. I guess I would hate to see the 40 and 357 fade into obsolescence.

    • Rusty Myers

      Not likely especially the .40 S&W to many cops are now carrying that far more then the 9MM or 45ACP

  • Scott Hemmelsbach

    This article answered some very basic questions for me. I believe the .357 Sig is an unsung hero hiding just out of sight for many who have not at least tried it. The ballistics are incredible! I own a Glock 27 (.40 S&W) and have a .357 Sig conversion barrel. I believe I now have the best of both worlds. If you haven’t tried the .357 Sig, at least give it an honest try.

    • Mambo Dave

      I found this discussion and article just now. I have to agree that – not as a fanboy nor owner, but just as an observer – this article was written too early in the .357 Sig life span. We have had a few national agencies switch to it, and now some major police forces are switching to it as well. A sizeable local police force just went to it after giving up on Glocks (documented issues witnessed by multile Glock armorers that Glock would not acknowledge – it wasn’t that Glocks are junk, but that the company refused to acknowledge a design flaw), and are quite happy with the .357 Sig after a good amount of training, their own ballistic gel tests, etc. I am certainly more open to the round. now, than I have ever been.

      • clcntx

        It was written in 2014 but it does appear that the opinions are from 2004. I don’t understand the reference to Glock in point number 2 above or in your post. Glock has several models chambered for 357 sig. Glock pushing the 40 or police giving up on Glock therefore makes no sense relative to the cartridge.

        • http://www.luckygunner.com/lounge LG Chris

          Regarding the second point in the article, when .357 Sig was initially released in 1994, Glock had been pushing .40 pretty hard and offered the G22/G23 cheap to LE departments, leaving less room in the LE market for a new cartridge from Sig. Glock did eventually offer .357 models of their own in 1998, but the fact that the market was already flooded with Glock 22s so early in the life cycle of .357 Sig almost certainly hurt its chances of becoming as popular as it could have.

  • Paul M. Sebula

    I see lots of LE departments switching from the 40 and .45 ACP to .357 SIG

    • Nate Opgenorth

      Depends on where you are. Allot of Highway patrols dig the .357 SIG. Its been adopted by some major LE agencies for sure but not too many have done it. FBI is going back to 9mm, .40S&W is still popular and .45GAP has actually replaced .40S&W in at least two State Highway patrol agencies. And of course .45ACP still has a cult like following and rightfully so…

  • Richard Hoepfner

    I’ve owned a S&W M&P for a few years now. I soon bought a .40 barrel for it. I love both. Both more powerful than my 9mm pistols.
    I carry with the. 357sig scuzzy I can.

  • srsanbo

    Late to this article, but wanted to chime in. The cartridge is unique – it is more accurate to describe it as a cut 10mm case necked down to accept a .355 diameter bullet than a 9mm bullet in a necked-down .40 case. The .357 Sig is actually slightly longer than the .40. I got a used LE G31 and love it. Same form factor as my G17 and can use the same holster and mag holders, easily converted to .40 w/ barrel and 9mm (barrel and mags). I appreciate the extra recoil impulse when practicing at the range, as it makes me better with the G17. The extra terminal energy may come in handy one day, hopefully not, but I feel more confident carrying 1500+ fps 125gr. rounds from Underwood.

    • David Doucette


  • paul

    What about 10mm? – That round seemed to gain a fair following fairly quickly, and it seems to remain fairly popular.

    • Rusty Myers

      Have a Glock model 20 in 10mm and it’s just awesome !! I highly recommend it, if they could
      Get the ammo down to a reasonable cost it would be perfect

      • clcntx

        The only problem is that the vast majority of the ammo is loaded down to be almost identical to 40 S&W. You have to buy expensive ammo like Buffalo Bore or load your own, otherwise the 10mm is pointless. Unfortunately I bought about 500 rounds of Remington for my Glock 20 before I was aware of this.

        • David Doucette

          Underwood has some great ammo.

  • Benedicto Colon

    I put a conversion 357 barrel to my Glock 23 and I love it !!

  • xaztec

    I think the main factor, at least now, is ammo price and availability. I’m into wheel guns .357 mag) but ammo is so expensive, even. 45 is significantly cheaper. .357 sig ammo is even more than .357 mag ammo. If the price came down close to that of the. 40, I’d make the investment but not going to buy a gun (or coversion) that I won’t be able to afford to use.

  • Rusty Myers

    9MM, 45ACP I don’t think so most all the police agencies where I live have traded up to the .40
    More power then the 9 and double the capacity
    Of the 45, a no brainer !! I think the one that is
    Heading to the shelf is the 357 Sig just not enough
    Interest however I have a Glock model 20 and am
    Thinking about getting the conversio. As I have heard
    Some good things

  • mudmann

    The 357sig..is here to stay…this article is inaccurate,and ignorant at best..the sigs terminal ballistics are far superior to the 40s&w,9mm45acp…only the 10mm with hot loads can duplicate a sigs wound channel..
    I know this from years of shooting ALL these rounds…and from years of killing hogs,coyotes and anything that doesn’t belong on the farm with them.. a lot of folks just look at the fps..and ft/lbs…not ever shooting these rounds at anything..including paper..then they feel qualified to comment on such..lmao…
    The glock g32 loaded with 125gr. Underwood ammo..is as close to perfection as a duty,self-defense, woods carry pistol ever created..and there is a plethora of federal agencies that feel the same.. shoot some of these rounds,..before you go shooting off at the mouth.

  • Jimmy

    Calibers don’t catch on because of bad or no press, from gun writers and gun salesmen who push their own favorite established cartridge.

  • Jimmy

    The 10mm and 357 Sig are much better than the Nazi 9mm Luger,the 40 Short and weak or grandpa’s 45ACP.Too many pistol shooters are wimps,revolver shooters aren’t afraid of 44 mags or the mild 357 mag.We all know that the supermen of the FBI pussied out on the 10mm.

  • Freddy

    So basically, people are not intelligent enough to understand muzzle velocity and energy exchange.