.357 SIG

01 / At a glance

The basics

Origin

United States / Switzerland

Introduced

1994

Ignition

Centerfire

Case form

Rimless, bottleneck

Diameter

9.0 mm

Case length

22.0 mm

Rounded values to help you identify the cartridge, not manufacturing drawings. See the cited standard for exact dimensions and tolerances.

A short history

SIG Sauer and Federal Premium developed the .357 SIG and introduced it in 1994. The SIG P229 was the first production pistol chambered for it. The goal was to match the performance of a 125 grain .357 Magnum load, which law enforcement had long respected, in a standard-size semi-automatic pistol.

The designers used a bottlenecked case. The bottleneck helps feeding and lets the case hold a lot of powder behind a 9mm-diameter bullet. The cartridge shares its case head and basic dimensions with the .40 S&W and the 10mm Auto, so many .40 S&W pistols can be converted to .357 SIG with a new barrel.

A number of national and state law enforcement agencies adopted it in the years that followed. Over time many agencies moved to 9mm pistols, citing the cost and availability of ammunition and modern 9mm bullet designs. The .357 SIG remains in production, and it has kept a following among shooters who like its speed.

Why people choose it

The first reason is speed. A 125 grain bullet leaves a 4 inch barrel at about 1,350 ft/s, and a 115 grain bullet is faster still. That speed gives a flat path and fast expansion in hollow point bullets.

The second reason is penetration. The bullet has a lot of velocity and the bottleneck case holds a good load. Some shooters value that for shooting through barriers such as car doors and windshields, though results depend on the bullet and the barrier.

The third reason is the pistol. Because the cartridge shares dimensions with the .40 S&W, many pistols can be converted with a barrel swap, and magazines often interchange. A shooter who owns a .40 S&W can add a .357 SIG barrel at modest cost.

Specifications at a glance

Values are rounded for reference. Exact dimensions and tolerances are in the SAAMI and C.I.P. standards cited at the end of this page.

Strengths and limits

The .357 SIG is a fast pistol cartridge with a sharp report. It should be judged as one.

It is an effective cartridge, and many shooters who learn to handle it enjoy it. A shooter who wants cheap practice and a wide choice of pistols and ammunition will find the 9mm a more practical choice.

It helps to be honest about the trade. The .357 SIG gives more speed than a 9mm, and the 9mm gives better bullets for the money, easier shooting and a much wider choice of pistols. Modern 9mm defensive bullets have closed much of the gap in performance, which is one reason many agencies moved back to it. Choose the .357 SIG because you like what it does, not because you think it is a magic round.

Barrel and slide wear

Because the cartridge runs at higher pressure and speed than a 9mm, it can put more stress on a pistol, and some parts can wear faster. Use a pistol made for the cartridge, and follow the maker's guidance on recoil springs and maintenance.

Ballistics

The tables and charts below show one common factory load, a 125 grain full metal jacket bullet at 1,350 ft/s from a 4 inch barrel, with the pistol zeroed at 25 yards.

For context, the same published table lists the load at 506 foot-pounds at the muzzle. Standard 9mm loads usually run at roughly 1,100 to 1,200 ft/s in a similar barrel, so the .357 SIG is faster, but the difference in energy is modest compared with the difference in recoil and cost.

Reading the numbers

With a 25-yard zero the bullet falls about half an inch at 50 yards, 2 inches at 75 and 6 at 100. A 10 mph crosswind moves it about 1 inch at 50 yards, 3 at 75 and 5 at 100. Velocity drops from 1,350 ft/s at the muzzle to about 1,080 ft/s at 100 yards, and energy from about 506 to about 323 foot-pounds.

These figures show why the cartridge is called flat-shooting for a pistol. Inside 50 yards the drop is small enough to ignore. Most defensive shooting happens at a few yards, where velocity and penetration matter more than path.

Recoil and shooter comfort

Recoil is sharp. In a full-size pistol of 28 to 30 ounces, the .357 SIG gives a snappy push, more than a 9mm and a little more than a .40 S&W. The muzzle blast and noise are also greater than for a 9mm.

It takes practice to shoot fast and accurately. A good grip and a firm stance help, and the cartridge rewards a shooter who trains. A new shooter may find a 9mm easier to learn on.

How to choose ammunition

Choose by purpose first. Ammunition for the .357 SIG is made by Federal, Speer, Hornady, Winchester and several others.

Bullet weight matters. A 124 or 125 grain bullet is the most common and gives the speed the cartridge is known for. A 147 to 150 grain bullet is slower, with less sharp recoil and more penetration. A lighter 115 grain bullet is faster still. Try a few loads in your pistol, and choose the one that shoots accurately and feeds without trouble.

Use ammunition made for the cartridge

Buy factory ammunition from a known maker. Do not use a .357 Magnum cartridge in a .357 SIG pistol. The cartridges are not interchangeable, and the .357 Magnum is a longer, rimmed revolver cartridge.

Cost of practice

Practice ammunition costs more than 9mm, so many shooters fire fewer rounds. A shooter who wants a good number of practice rounds should plan the budget, and consider dry-fire practice, which costs nothing and builds the same trigger skills.

How to choose a pistol

The right pistol depends on how you will use it. These are the points that matter most.

• Size. A full-size or compact pistol handles the recoil well. A subcompact kicks harder.
• Weight. A heavier pistol with a metal frame soaks up recoil better than a light polymer pistol.
• Barrel conversion. Some pistols, such as many .40 S&W models, can take a .357 SIG barrel. Check with the maker first.
• Sights. Choose sights you can see clearly. Night sights suit defensive use.
• Reliability. Test the pistol with the ammunition you plan to use, and shoot enough rounds to be sure.
• Fit. Hold the grip, reach the trigger and check the magazine release before you buy.

Zeroing and practice

A 25-yard zero is common for pistol shooting, and for a defensive pistol many shooters use a 15 or 25 yard zero. The path is flat enough that you can hold at the target out to 50 yards with only a small hold-over.

Practice trigger control and grip. Dry-fire practice with an unloaded pistol improves your trigger press at no cost. At the range, shoot slowly at first, and add speed when your hits are good. Confirm your point of impact with your defensive load, since it can differ from practice ammunition.

Practical uses

The cartridge sits in an unusual place. It is neither the cheapest nor the most common, and it is not the most powerful. People who choose it usually do so for its feel and its history, and they accept the cost. That is a reasonable choice as long as the shooter practices enough to use it well.

Personal defense

This is the main use. The speed and penetration of a good hollow point suit a defensive pistol. Choose a load that expands reliably and practice with it.

Carry and storage matter as much as the cartridge. A pistol that is comfortable to carry gets carried, and one that is left at home does not help. Choose a good holster, practice the draw safely and keep the pistol secure when you are not carrying it.

Law enforcement

Several agencies adopted it, drawn by its penetration and speed. Many later changed to 9mm because of cost and availability.

Competition

Some competitors use it in practical shooting events. It is not as common there as the 9mm.

Field and outdoor carry

With a hard cast bullet, it can be used as a backup against animals at close range. For this a larger cartridge, such as the 10mm Auto or a revolver, gives more margin.

Target shooting

It is an accurate cartridge, and fun to shoot. Because of cost, most people shoot it less than they would a 9mm.

.357 SIG vs similar handgun cartridges

The table lists the cartridges most often compared with the .357 SIG. Figures are rounded and use SAAMI maximum average pressures.

Against the 9mm Luger, the .357 SIG is faster and has a flatter path, with more recoil and cost. Against the .40 S&W, it shoots a lighter bullet at higher speed. Against the 10mm Auto, it is milder and smaller. Against the .357 Magnum, it matches the speed of the 125 grain load in a semi-automatic pistol.

Care and storage

Clean the barrel, the slide and the feed ramp after each session, and use a light oil on the rails. Replace recoil springs on the maker's schedule, since a high-pressure cartridge wears them faster. Check the magazines for wear. Store the pistol unloaded in a dry place. Keep firearms and ammunition locked and out of reach of children and unauthorized users.

Safety and common mistakes

• Do not confuse the .357 SIG with the .357 Magnum, the .40 S&W or the 9mm Luger. Read the marking on the barrel and the slide.
• Treat every firearm as loaded. Keep your finger off the trigger until your sights are on the target.
• Know your target and what is beyond it. A handgun bullet can travel more than a mile.
• Check that the barrel is clear and the chamber is empty before loading.
• Wear eye and ear protection at the range.
• Use only a barrel made for the cartridge when converting a pistol, and follow the maker's instructions.
• If you reload, use only published data from a current manual and start low. This page does not contain loading data.
• Store firearms unloaded and locked, and keep the ammunition apart.

Sources

Sources reviewed · 29 October 2026

1. Wikipedia · .357 SIG ↗
2. Federal · American Eagle 357 SIG 125 gr FMJ ↗
3. SAAMI ↗