[.357 SIG]: Best Ammo & Post-Mortem Review

.357 SIG is a weird cartridge.   It’s one of those less-common cartridges kinda like .44 Magnum that gets a lot of hype but no one really uses it, and no one knows why.  Nobody really knows what to do with it at this point. It was intended to be a contender in the pistol world alongside the 9mm, .45ACP, and the (at the time) recently-released .40 S&W. Nowadays, the .357 SIG hasn’t really caught on except in some niche circles…but it hasn’t gone away either.

I’ve heard all kinds of things about the .357 SIG over the years, some good and some bad, some true and some false.  I think it’s time to set the record straight. There’s nothing inherently bad about the .357 SIG, and it does have a small but loyal following that swear by it.   There’s also a reason why it hasn’t really caught on.  A few reasons, actually. Let’s put aside the hype and really look at the truth behind this cartridge, that way you can decide for yourself what to do with the .357 SIG.

History of the .357 SIG

Back in the early 90’s, someone at firearms giant SIG Sauer got a bug up their butt about the .357 Magnum.  Specifically, they wanted to recreate 125gr .357 Magnum performance out of a four-inch revolver, but in an auto-loading pistol.

SIG partnered up with another big name in the firearms world to make this happen: Federal Cartridge, now called Federal Premium Ammunition.  You will know this name from the massive slice of the ammo section they own at your local sporting goods store. Together, they set out to recreate the performance of the popular .357 cartridge in a bottle-necked cartridge that would have less recoil, but similar overall ballistics. They worked to create a cartridge based on the 10mm Auto case that could be necked-down for a .357 Magnum projectile, and that could handle higher pressures to surpass the .40 S&W, and be on par with the .357 Magnum. Around 1994, what they ended up with was a cartridge that was a hair longer than .40 S&W, with slightly less recoil, firing a 125gr (almost 9mm) bullet with .357 Magnum energy.  Specs stated it would have an 18-degree shoulder, a short neck measuring 0.275 inch, utilize standard small pistol primers instead of magnum ones. Thereafter, they would switch to a 9mm projectile that was slightly smaller for ease of reloading, and better velocities. Shortly after, SIG released the SIG Sauer P229 which was the first commercially-produced firearm chambered for the new cartridge.  It could also be easily modified to shoot the .40 S&W simply by switching out the barrel.

The P229, a variant of the popular P226 designed for the higher pressures and increased slide velocities of the .357 SIG and the .40 S&W.   As far as the cartridge itself, it found success with a number of LEO agencies, but it didn’t quite reach the widespread adoption that SIG and Federal hoped for (for reasons I’ll get to in a minute) but this adoption by police forces is likely what has saved the cartridge.

Performance of the .357 SIG

Performance-wise, SIG and Federal hit it out of the park with their new round.  They hit all their design goals and ended up with an extremely accurate and flat-shooting round that matches the .357 Magnum, even if only the smallest .357 Mag bullets. While .357 Magnum starts to outstrip the .357 SIG in terms of raw energy with anything bigger than a 125gr projectile, the .357 SIG still does a great job of replicating the ballistics, particularly the very flat trajectory, of its design inspiration. Of course, the nature of .357 SIG pistols versus .357 Magnum revolvers means that you get more or less double the number of rounds on tap with the SIG which is more than enough to outweigh the lesser velocity and energy for me. Modern firearms doctrine has very much moved on to “more bullets = more better” instead of “bigger bullets = more better” so the .357 SIG actually exceeds the original in this regard. The rounds are also smaller and lighter than the .357 Magnum’s, which makes carrying extras a lot less of a pain.  That said, impact performance, particularly with the larger 160gr bullets at the upper end of the .357 SIG’s size range is still impressive, and is certainly an improvement over the 9mm (even though the difference is getting smaller and smaller every year with improvements in projectile design). For example, the Virginia State Police have recorded multiple instances where attacking wild dogs have been stopped by a single .357 SIG round, and investigations into the incident suggested that a single shot with a 9mm, given the same impact point, would have been insufficient. Now, this isn’t super scientific I know, so we’ll get to some actual numbers in a second, (and also it kinda sounds like Virginia has a wild dog problem, wtf Virginia?) but it is representative of some real-world usage of the cartridge, and some potential advantages it has over the far more popular 9mm. The one thing that I think really holds the cartridge back is muzzle blast.  The sheer sound and force of the projectile makes it a little less than comfortable to shoot for most folks, although actual recoil and muzzle flip are on par with the .40 S&W. Finally, the bottle-necked nature of the cartridge means that feeding problems are basically non-existent.  I’ve never once experienced a failure to feed or failure to go into battery with a .357 SIG firearm, which is no small feat.

This is because of that bottleneck design that causes the round to be fully seated as the slide goes into complete battery, after essentially being straightened and aligned by the larger section of the chamber before the namesake bottlenecking of the chamber. This also works well with the traditionally very flat-nosed bullets you find in the .357 SIG.  Flat-nosed bullets, whether hollowpoints or FMJs, are typically avoided because the flat plane of the nose can catch on feed ramps and cause malfunctions ranging from the annoying to the downright life-threatening. No such worries with the .357 SIG.  The design means no problems feeding flat-nosed FMJs or notoriously finicky hollowpoints.

Why It Never Caught On

Of course, all of that sounds really great, right? So why aren’t we all carrying .357 SIG guns instead of 9mm, .45, .380 or .40?

Actually, there are a few reasons. First and foremost, while SIG and Federal really wanted a compact, auto-loading cartridge that replicated the oomph of the .357 Magnum…not a lot of other people really cared.   You had the .40 S&W that was still new but had been out long enough to gain a bit of a following, especially amongst law enforcement and those who wanted an intermediate cartridge between 9×19 and .45 ACP.  While .357 SIG is superior to .40 in velocity and muzzle energy, the numbers aren’t enough to make a huge difference, certainly not in the minds of most people. In general, not a lot of folks care enough to read all the little numbers on the back of the ammo box, so .357 SIG’s improvements over .40 S&W weren’t widely realized until later when it was arguably too late for the round to really take off. Really it was just a case of a cartridge filling a need nobody really had. Those with a preference for higher-capacity would choose the extra 4-5 rounds they could get out of a similarly-sized 9mm over the .357 SIG, those looking for an intermediate handgun round already had .40 S&W, and those still ascribing to the “bigger bullets” theory still had the venerable .45 ACP.

So who was the .357 SIG really for?  

Law enforcement.  It seems like SIG and Federal wanted a round that would appeal to LEO’s and give them the easier shooting experience of the .40 with a little more power and a flatter trajectory.

And they did that.   They absolutely succeeded…it just wasn’t enough to pull more than a few state and federal agencies away from the calibers they already used. That lack of widespread adoption by law enforcement is what killed the .357 SIG’s chances at ever rubbing shoulders with the “big three”, and modern doctrine emphasizes shot placement and capacity over long-range accuracy or stopping power. Newer bullets with better terminal performance have lessened the gap between calibers, and modern 9mm ammo isn’t far behind .40 or even .45 ACP performance wise, but allows for many more rounds on tap and a much more controlled shooting experience. That’s why most police and even military handguns are going to be wielding 9mm over anything else. Maybe if more police departments, particularly large state agencies, had picked up the .357 SIG, things would be different, but as things stand, there aren’t a whole lot of folks who see the need for a .357 SIG handgun.

.357 SIG Today

Modern .357 SIG firearms like the P229 and the GLOCK 37, 38, and 39 are still carried by a number of law enforcement agencies, and even some federal agencies like the Federal Air Marshals and the Secret Service. The Glock 32 is also popular with CCW civilians and as an off-duty carry gun for police officers. A lot of state agencies that let officers have a bit of leeway with what they carry have also continued to allow the .357 SIG to be carried. However, while these groups continue to use .357 SIG, very few new agencies are picking up .357 SIG, and I was unable to find any evidence of a major law enforcement agency switching to it after 2014. Nowadays, it’s hard to even find .357 SIG on store shelves which is more or less the kiss of death for a pistol round.  Niche rifle rounds can find success with reloaders and can even rumble along in relative obscurity and be fine. The sheer massive availability of the 9mm, .45 ACP, .380 ACP, and .40 S&W, and thus the comparatively cheap prices of these rounds, means the .357 SIG will never really be able to compete, not in the wider commercial market.

The Future of .357 SIG

Where will .357 SIG be in five years?  Ten? I really don’t know.  I know that most everyone in law enforcement is going to 9mm.  I know most carry aficionados are going to 9mm. I know that most everyone that used .357 SIG does so for emotional “but I like it” reasons rather than reasons of science. But we gun people are an emotional lot, prone to thinking with our gut or our hearts instead of our heads.  Sure, the .357 SIG will probably never be as popular as the 9mm, but will it go away? I don’t think so.  That core of loyal users that have probably been shooting .357 SIG since the mid-nineties doesn’t show any signs of giving up on the cartridge

Best .357 Sig Ammo

If you do carry .357 Sig or you are planning on it soon, there are some great options when it comes to ammo. The downside? Well, .357 ain’t cheap compaired to some ammo – but it isn’t bank breaking either.

1. Speer Lawman, 125gr 

.357 Sig is not designed for plinking, it’s meant to be a duty cartridge and carried and serious people. As such – there isn’t much in the way of cheap plinking ammo, but there is decent priced training ammo. The Speer Lawman fills that role exactly. Reliable, clean shooting, and less than half the cost of carry ammo.

2. Sig Sauer 125gr V-Crown

Of course, Sig Sauer would offer some of the best duty ammo! As the testing done by Lucky Gunner prove, this ammo performs when you need it most.

Parting Shots

In short, I think the .357 SIG offers some definite benefits and is probably here to stay for at least a little while yet.  It’s a good cartridge with good performance, and despite not being the success SIG and Federal wanted, nothing can change the fact that this oddball cartridge works.   Maybe that’s enough What do you think of the .357 SIG? Do you own one, or are you thinking of getting one?  If you’re interested in more common calibers, take a look at our Best 9mm Ammo and our  Best .45 ACP Ammo articles!