March 1999

.357 Sigs: We Recommend Glock’s Reliable Model 31

A defensive handgun should always go bang, and the black Austrian gun did just that. Also worth a look is Sigís Pro 2340óbut donít bother holstering Smith & Wessonís erratic Sigma.

The annals of gunmaking are filled with stories of hot, new cartridges whipped up by wildcatters, or in some cases mainline manufacturers, that have gone on to long histories of obscurity or indifference among shooters. The .41 Magnum comes to mind as a prime example of a round that when introduced had all the credentials of a world beater: speed, power, and accuracy. But, today, finding a .41 Mag. on the range is like encountering an old friend you’ve not spoken with in ages. You wonder what he’s been up to.

With this backdrop, we wonder what the .357 Sig’s “future history” will be. This chambering, sired from a cooperative effort between Sig Sauer and the Federal Cartridge Company, is based on a .40 S&W case necked-down to accept a .357-size bullet. Naturally, this gives the .357 Sig plenty of pop; commercial Sig ammunition is loaded to almost .357 Magnum velocities. Typically, .357 Sig ammunition utilizes bullets that weigh from 125 to 150 grains. From a 4-inch barrel, 125-grain loads produce a muzzle velocity of around 1,350 fps and develop 510 foot-pounds of muzzle energy. The 150-grain loads run 1,130 fps and generate 420 foot-pounds. This compares favorably with .357 Magnum ammunition, which runs 1,450 fps and 580 foot-pounds with 125-grain bullets, and .357 Magnum 158-grain loads are good for 1,240 fps and 535 foot-pounds.

Though the .357 Sig has the ballistic credentials to take its rightful place alongside other midsized handgun powerhouses, it nonetheless has been slow out of the gate. After the .357 Sig was introduced in 1996, its namesake company Sig Sauer was the only manufacturer that made pistols in this caliber. Today, however, other handgun makers have jumped on the Sig’s wagon and offer the gun aficionado a decent selection of products chambered for the round.

To see which of these guns is the best buy, we acquired models from three well-known makers and compared them head to head. Our guns included the:

• Glock 31, $559;
• Sig Pro 2340, $596;
• Smith & Wesson Sigma; $393

All of these full-size defensive pistols had polymer frames, 10-round double-column magazines and fixed sights. Unloaded, they weighed from 25 to 29 ounces with barrels ranging in length from 3.75 inches to 4.5 inches. The Glock and the Smith & Wesson were striker-fired pistols with double action only–style triggers, while the Sig had a traditional firing mechanism with an external hammer and a double-action/single-action trigger.

Click here to view the Accuracy and Chronograph Data


Our testing showed the Glock outdueled the Sig Pro for top honors, showing utter reliability and first-rate human engineering. Some shooters familiar with other Sig handguns may also like the Sig Pro’s controls. The S&W Sigma, in contrast, malfunctioned too often for our tastes, which knocked it out of the running.

To come to these conclusions, we test-fired the guns head-to-head with three brands of commercial ammunition and graded them on accuracy, handling, malfunctions, and other matters critical to the performance of a self-defense gun—hardnosed, unbiased fact-finding and evaluation you won’t find in any other gun magazine. Accuracy testing was conducted outdoors at 25 yards using a sandbagged pistol rest and open sights. Here are the results of our examinations:

Glock 31
Our Recommendation: This gun is our first choice. The Glock 31 wasn’t handsome, but it was reliable. Also, its human engineering was first rate, and accuracy was better than we expected.

Click here to view the Glock 31 features guide


In our view, defensive firearms must first be reliable. Glock pistols are known for functioning flawlessly, and our Model 31 wasn’t an exception. The pistol readily digested all of the .357 Sig ammunition we fed it. In fact, it was the only handgun in this test that was 100-percent reliable. This alone was enough to give the Glock the top spot in this test.

However, the Glock 31’s accuracy was also slightly above average. Its smallest five-shot groups averaged 2.58 inches at 25 yards with both Remington 125-grain and Federal Premium 150-grain jacketed hollow points. We also obtained decent 3.18-inch groups with UMC 125-grain metal case ammunition.

Moreover, our shooters thought the Glock 31’s biggest strength was its handling qualities. The pistol was muzzle-heavy enough to make the gun feel stable, without significantly slowing target acquisition. The shape of the frame and its integral grip allowed the pistol to sit unusually low in the shooter’s hand, positioning the hand closer than normal to the bore’s axis. This improved the shooter’s ability to control the gun, especially when firing fast follow-up shots. Muzzle flip generated during recoil was only a little heavier than what a Glock .40 S&W pistol produces. Like all Glock pistols, the Model 31’s controls were user friendly. The manual trigger-blocking safety was built into the trigger. When the shooter pulled the trigger, the safety disengaged and allowed the trigger to move rearward for firing. Right-handed shooters could readily depress the magazine-release button at the rear of the trigger guard with the thumb of their shooting hands, while left-handed shooters could just as easily depress the release with their trigger fingers. The slide-catch lever on the left side of the frame worked positively. The Glock 31’s Safe Action trigger wasn’t a true double-action-only trigger, because it didn’t have a second-strike capability. However, the pull felt like a lightweight double action–only pull. The trigger’s long movement let-off at a reasonable 6.5 pounds with no noticeable overtravel.

Minor faults we found with the Glock 31 included problems with the magazine, wherein inserting more than seven rounds into either of the two 10-round steel-reinforced polymer magazines required extreme effort, even when using the loading tool provided with the gun. Both of the sights were made of black plastic, which we don’t think will be as durable as steel.

Sig Pro SP2340
Our Recommendation: Right-handed shooters familiar with other Sig handguns may prefer the Pro over the Glock. We think left-handed shooters won’t like the location of the Sig Pro’s controls.

Click here to view the Sig Pro SP2340 features guide


Most crucial in our evaluation of this gun was how it functioned after the usual break-in period. At the range, our Sig Pro’s operation was almost faultless. It failed to feed once with Remington 125-grain jacketed hollow points during the first 75 rounds. However, there were no other malfunctions afterward. Since we only experienced one stoppage, and it occurred within the normal break-in period for a pistol, our shooters considered the gun to be reliable enough for defensive use.

Elsewhere, the Sig Pro combined the basic functionality of the manufacturer’s P-series pistols with several new and worthwhile features. Of the three pistols in this test, we judged the Sig Pro to be the most evenly balanced, allowing the gun to sit squarely in the hand. Though this model weighed almost 2 ounces less than a .357 Sig P229, the manufacturer’s standard metal-framed .357 Sig/.40 S&W pistol, it was at least 3 ounces heavier than either of the other pistols in this test. This extra weight lessened felt recoil, but also slowed target acquisition, in our view. Two one-piece grips were supplied with this pistol. One of the grips was made of black plastic and had molded stippling for slip resistance, while the other was made of black rubber with an untextured finish. The overall size and feel of each grip was basically the same as that of the Sig P229. Both grips contributed to a secure and reasonably comfortable grip surface, but not as good as the Glock 31, we thought.

The Sig Pro’s controls were similar to the P229’s, but their shapes were different. The slide catch on the left side of the frame was a traditionally-shaped lever with a very long neck. The decocking lever, which was just in front of the slide catch, had a practical, curved shape. The magazine release was a triangular button at the left rear of the trigger guard. A right-handed shooter could manipulate the controls with the thumb of his shooting hand without shifting his grip, but only the magazine release was well situated for lefties, in our estimation.

The Sig Pro’s accuracy wasn’t as consistent from load to load as the Glock 31, but it did produce the smallest groups of the test with UMC 125-grain metal case ammunition. This load yielded five-shot groups that averaged 2.23 inches at 25 yards. Groups opened up to 2.82 and 3.00 inches with Federal Premium 150-grain and Remington 125-grain jacketed hollow points, respectively.

Overall, the Sig Pro’s workmanship was above average. Its metal and synthetic parts had no cosmetic or structural flaws, and the stationary components attached to the polymer frame, such as the large, steel slide rails, were solidly pinned in place. Moving parts, such as the blackened stainless-steel slide and blued-steel barrel, had only modest play. The trigger had a smooth double-action pull that released cleanly at 10 pounds, but we felt its 6-pound single-action pull was about 2 pounds too heavy.

Smith & Wesson Sigma
Our Recommendation: We don’t think you should buy this handgun. The Smith & Wesson Sigma seems to us to be a poor imitation of the Glock. Its trigger was comparatively heavy and inconsistent, handling was mediocre, and its accuracy was lackluster. Most important, it was unreliable in our tests.

Click here to view the Smith & Wesson Sigma features guide


In our opinion, the Smith & Wesson Sigma’s functioning was unacceptable for a defensive pistol. After break-in, it failed to feed three times. These malfunctions occurred once with Federal Premium 150-grain jacketed hollow points and twice with Remington 125-grain jacketed hollow points. Furthermore, the pistol failed to fire six times due to light firing-pin strikes. This occurred once with the Remington load, twice with the Federal load, and three times with UMC 125-grain metal case ammunition. All of the misfired rounds went off when we ran them through the gun a second time.

During firing, we also found that the Sigma’s point of impact changed drastically when we switched bullets weights. At 25 yards, the point of impact matched the point of aim of the Sigma’s sights when using Federal Premium 150-grain jacketed hollow points. However, the gun shot 5 inches high and to the left with the Remington and UMC 125-grain ammunition. Still, though the Sigma was the least accurate pistol in this test, we felt its accuracy was adequate for defensive work. Its smallest five-shot average groups, 3.48 inches at 25 yards, were obtained using Remington 125-grain jacketed hollow points. UMC 125-grain metal case ammunition came in second with 3.68-inch groups. Federal Premium 150-grain jacketed hollow points brought up the rear with 3.95-inch groups. One of the reasons for this Smith & Wesson’s lackluster accuracy was its poor trigger. Like the Glock 31, the Sigma had one trigger pull and no second-strike capability. However, its trigger movement was as heavy as a true double action-only pull. Consequently, the trigger’s release was several pounds heavier and much less consistent than the Glock’s. The pull let-off at anywhere from 10.5 to 13 pounds.

The Sigma’s controls were similar to the Glock’s. The manual safety, which was built into the bottom portion of the two-piece trigger, prevented the trigger from moving rearward if it wasn’t depressed by the shooter’s trigger finger. The slide catch, a 1-inch-long lever on the left side of the frame, worked positively. The magazine release, a tear-drop-shaped button at the left rear of the trigger guard, was protected from being inadvertently depressed by the grip’s thumbrest. However, the thumbrest also obstructed the shooter’s access to the release. In handling, the Sigma was less muzzle heavy than the Glock. This lessened muzzle stability with the arms extended, but made target acquisition a little faster. In our range tests, the grip afforded a secure and fairly comfortable grasp, but the shape of its backstrap caused the front sight to align high when the gun was pointed. The long tang at the top back of the frame did a decent job of spreading recoil over a large portion of the shooter’s hand. Nevertheless, the Sigma’s muzzle jumped more than the other .357 Sig pistols in this test.

Gun Tests Quick-Buy Advice
Glock 31, $559. Buy it. This gun functioned reliably, felt great, and shot accurately enough for a defensive handgun.

Smith & Wesson Sigma, $393. Don’t buy it. In our tests, it failed to feed and failed to fire—the kisses of death for a self-defense pistol.

Sig Pro 2340, $596. A good choice if you’re already a Sig pistolero, but lefties should go with the Glock.