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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.