SIG Sauer's New P320 AXG Legion: Ultimate Striker-Fired 9mm Pistol

SIG Sauer's new P320-AXG Legion isn't your run-of-the-mill 9mm striker-fired pistol. It is the pinnacle of modern full-size handguns.

March 22, 2024 By Joel J. Hutchcroft, Editor-in-Chief

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The first thing I noticed about SIG SAUER’s new duty-size P320-AXG Legion pistol is the integral two-port expansion chamber/compensator at the muzzle end of the slide. Each port is 0.24 inch wide and 0.66 inch long, stretching across almost the entire width of the top of the slide. In addition, together they extend about 0.9 inch beyond the end of the pistol’s barrel, bringing the slide’s length to 7.5 inches. This is newsworthy because the P320-AXG Legion is the first P320 with a built-in expansion chamber. But that’s not the only feature that makes this version of the tried-and-true P320 pistol unique.

SIG AXG Legion Modern Features

sig-p320-axg-legion-pistol-02 — The new SIG Sauer P320-AXG Legion 9mm pistol features SIG’s aluminum AXG grip frame; a special, extended magwell; and custom Hogue G10 grip panels.

The all-metal 9mm P320-AXG Legion also has a special frame. In fact, it’s made of aluminum alloy. It has an integral three-slot Picatinny accessory rail built into the dustcover. It has a squared trigger guard, with a small patch of checkering on the front surface. The Alloy XSeries Grip (AXG) grip frame is sculpted, and the trigger guard sweeps up to allow a high-hand grip. The frontstrap of the grip frame is checkered. The backstrap of the grip frame is textured in a pattern that mimics the texturing on the custom Hogue Legion G10 grips. And the top of the backstrap has an ample beavertail. At the bottom of the grip frame is a special, extended magwell. The entire frame, except for the magwell and the controls, is finished in Legion Gray Cerakote. The magwell is matte black, as are the grip panel screws.

sig-p320-axg-legion-pistol-03 — The pistol comes with three double-stack magazines that hold 21 or 10 rounds of 9mm ammunition. They feature checkered aluminum baseplates/bumper pads.

The new pistol comes with three double-stack magazines. You can get them in 21-round configuration or 10-round configuration. Shooting Times received three 10-rounders. They have metal bodies with numbered witness holes; removable, checkered aluminum baseplates/bumper pads that sport the Legion symbol; and polymer followers. “Made in Italy” is stamped on the right-hand side, and “SIG SAUER” and “9mm” are marked on the left-hand side. They wear a deep, dark, polished black finish. The flat and skeletonized XSeries trigger is matte black and measures 0.36 inch wide. The fingerpiece has a slight ledge at the very bottom, and I found it to be quite convenient as it provided an extra bit of control. And speaking of trigger control, our P320-AXG Legion has one of the most consistent trigger pulls I have felt on a striker-fired 9mm pistol. It has some take-up but no detectable overtravel. And it broke consistently at 4.5 pounds of pull over a series of 10 measurements with an RCBS trigger pull gauge. There was no more than 3 ounces of variance over all 10 measurements.

sig-p320-axg-legion-pistol-04 — The XSeries flat trigger is skeletonized and finished in matte black. Our sample’s trigger pull averaged 4.5 pounds, with no more than 3 ounces of variance over 10 measurements.

Back to the slide. The slide is attractively contoured, and as is the rage today, the top is cut for installing a red-dot optic. On this pistol, the filler plate is ahead of the rear sight, in contrast to some of the custom and semicustom Model 1911s that have the rear sight forward of the slide cut. It is made to accommodate SIG SAUER ROMEO1 Pro and ROMEO2, Leupold DeltaPoint Pro, and Trijicon RMR red-dot optics. The slide has angled grasping grooves at the rear and at the front. They each measure 0.19 inch wide, and there are six on each side up front and seven on each side at the rear. The sights are SIG’s Xray3 day/night sights that feature tritium dots (two on the rear sight and one on the front sight). The front sight’s dot is surrounded by a fluorescent green ring, and both sights are dovetailed into the top of the slide, making them drift adjustable. The sight radius is 5.9 inches. Like the frame, the slide is finished in Legion Gray Cerakote, except for the black sights and the black slide cut filler plate. The takedown lever, the slide stop, and the magazine release are located in the traditional places, and they are finished in matte black.

sig-p320-axg-legion-pistol-05 — SIG’s Xray3 day/night sights feature tritium dots, and the rear sight has a square notch. It is drift adjustable for windage.

The magazine release button is checkered, and the slide stop is ambidextrous. There is no manual thumb safety on this model. The black, ramped barrel is 3.9 inches long, and its chamber is throated and polished. The muzzle has a recessed crown. The pistol is 8.2 inches long overall, weighs 36.1 ounces, is 1.6 inches thick at the magwell, and is 5.5 inches tall without a red-dot optic. It comes in a foam-lined hard carrying case along with the three magazines, a cable lock, an operator’s manual, and a couple of decals.

P320 AXG Legion Range Results

With its all-metal construction and AXG grip frame, the SIG Sauer P320-AXG Legion was extremely comfortable to shoot. Recoil was hardly noticeable, even with the hottest factory loads I tested. As for accuracy, well, the pistol did not disappoint in that department, either. Overall average accuracy for three, five-shot groups with nine different 9mm factory loads was 3.03 inches. The details of each load are listed in the accompanying chart, but briefly, my best individual string came with the Winchester Defender 147-grain JHP ammo. It was just over 1.0 inch, and that’s at 25 yards. As the chart shows, the three-group average for that loading was 2.25 inches. Interestingly, it was not my most accurate loading, on average, with the pistol. That distinction goes to the Federal 150-grain HST load, which averaged 2.00 inches for three, five-shot groups. I suspect the fact that it was the softest-shooting load has something to do with me being able to shoot it so accurately.

sig-p320-axg-legion-pistol-06 — The front sight features a fluorescent green ring around the tritium dot. Note the slide’s integral two-port expansion chamber/compensator at the muzzle end of the slide.

The load with the highest average velocity was the SIG SAUER 115-grain JHP, and it averaged 1,230 fps with an extreme spread of 20 fps and a standard deviation of 9 fps. I don’t have to tell you that those are impressive figures. For the record, velocities were measured 12 feet from the gun’s muzzle with a Competition Electronics ProChrono Digtal chronograph using its indoor light setup. All in all, the P320-AXG Legion is an excellent pistol. It shoots comfortably—and accurately. Reliability is top-notch, as I didn’t have a single failure to feed, extract, or eject over the course of my shooting session. It has some very special features that reflect its high quality and enhance its performance.

sig-p320-axg-legion-pistol-07 — The new P320-AXG Legion is a duty-size 9mm pistol with a 3.9-inch barrel, all-metal construction, and Legion Gray Cerakote finish.

And it’s part of the SIG SAUER Legion family, which means by purchasing it, you have the opportunity to register and join the SIG SAUER Legion. Doing that entitles you to a complimentary premium zippered pistol case and a challenge coin matched to your gun, plus it gives you members-only access to unique opportunities, special gear and other merchandise, and exclusive communications. SIG SAUER’s Legion firearms are state-of-the-art fighting tools, and the new P320-AXG Legion is a fine addition to the line. It is most certainly not a run-of-the-mill 9mm pistol.