What? Metal-frame striker-fired pistols? Think about that for a moment; metal-frame pistols are slowly disappearing. Sure, the 1911 platform uses a metal frame, and so do other older hammer-fired designs from SIG, Beretta, and CZ, but nearly every striker-fired pistol uses a polymer frame. Gun nuts did a double take when Rock Island Armory (RIA) debuted the STK100 striker-fired 9mm in 2021. It looked like just another Glock clone, except for one significant design difference. The STK100 uses an aluminum frame. There are other features that make this Philippine-made pistol stand out, but the metal frame is unique. This sent us on a quest for metal-frame striker-fired 9mm pistols. Are these guns just unicorns, or are there others available to buy?

We tested the Walther Q5 Match Steel Frame a few years ago and thought the steel frame helped mitigate recoil and allow for a fast follow-up shot. But that was a competition pistol, not a defense pistol. One gun that came to mind was the Kahr K9. Kahr built its reputation on the compact metal-frame K9 pistol, so we acquired a Model K9, which features a stainless-steel frame and smooth trigger-cocked striker-fire mechanism.

Another gun is the new metal-frame variant of the SIG P320 called the P320 AGX Pro. As you may recall, the P320 pistol system allows the user to drop the trigger mechanism into any size polymer frame, and now a metal frame as well.

It’s usually interesting to know where gun designs originate, and here, the original 9mm metal-frame striker-fired pistol is a Luger P-08. As you know, the 9mm cartridge debuted with the P-08. While the P-08 in its day was an effective weapon, they are expensive and finicky with ammo. Luckily, one of our staff has a Luger, an Interarms P-08 model, and we wanted to experience the original P-08 and put it into context with current guns, so we ran an the Interarms during the test, but we concentrated our evaluation on the modern variants.

While they are all striker-fired, the trigger design was different on all four, and all felt different when firing. The P-08 uses a pre-cocked striker, so it is actually a single-action trigger pull, similar to the XD models made by Springfield Armory. The other three guns have a longer double-action trigger pull. RIA and SIG pre-load the striker, so there is a bit of mushiness in the trigger. The Kahr uses a trigger-cocking DAO that is super smooth and has a super-long stroke.

We also wanted to judge if the added weight a metal-frame pistol provides is a net pro or con. Does a metal frame help with recoil control? How does the pistol balance in hand? Does it make the pistol more difficult to carry concealed?

We fired both training rounds and defense rounds with different bullet weights and types to see if a pistol favored one cartridge over another. Ammo included Defender 115-grain full metal jackets, Armscor 124-grain FMJs, and Remington Golden Sabers with 147-grain bonded jacketed hollow points.

We tested for accuracy using our range bag as a rest, then ran a Mozambique Drill (also called a Failure Drill) at 10 yards — two to the body and one to the head — on cardboard silhouettes to evaluate ease of use in speed and precision shooting. We also fired a Failure Drill at 5 yards, starting at low ready, and all three shots must be fired between 3 and 4 seconds. In the end, we experienced four very different 9mm metal-frame striker-fired pistols.

Gun Tests Grade: A (OUR PICK)

$1200

We have evaluated the SIG P320 in the past in the M17 commercial equivalent of the US Military M17, P320 Carry, and the original P320 variant. These guns received B ratings due mainly to heavy trigger pulls. The P320 Carry received an A rating due to cost and accuracy and was a surprise to our test team. As you know, the P320 is unique in that the trigger mechanism is the serial numbered part, and it can be inserted in different-size grip modules, from compact to full size. The standard P320 grip is polymer, and the X-Series grip uses a polymer-tungsten material. With the X-Series grip, there is the ability to add weight to the pistol. The latest grip module is the AXG version, made of aluminum to provide more weight and a more classic SIG look. AXG stands for Alloy X-Series Grip and is perhaps the opposite direction of the original P320 design intent, which was a polymer-frame lightweight striker-fired handgun. The metal adds weight, an additional 5.8 ounces compared to the polymer P320. The P320 AXG Pro also addresses the trigger issue we had with older models. This new gun uses an X-Series trigger module, which made the X-Series pistols marginally better, but the X-Series trigger integrated into the AGX grip module is a great combination. The trigger has a flat face and it breaks at 90 degrees. The reset is also quick. In our opinion, the AGX Pro is very comfortable to shoot.

In the hand, we were smitten by this trigger and grip module. It feels like a classic SIG pistol but with flatter grip sides, nice trigger guard undercut, and extended beavertail. Some of our test crew also have experience with the X-Series tungsten-infused polymer-frame competition models, and in their opinion, the standard P320 grip was chunky, and the X-Series grip was flatter and more angular. The AGX Pro is different and a welcome addition. The frame module features Hogue G10 grip inserts in the side panels and backstrap. The G10 has a nice checkered texture that is not overly grippy. One can swap these out for others in a different colored G10, or walnut if you want to go retro ($120 at SIGSauer.com). The front grip strap is also checkered. A detachable metal magwell creates a wide funnel for fast reloads, slurping up the fine SIG double-stack steel magazines.

Controls consist of a large round magazine button at a good height, though we did have to slightly change our grip to dump an empty mag. The slide stop is ambidextrous and protrudes from the frame enough so the thumb of your firing hand can manipulate it. The take-down lever is typical SIG, which means it is easy to manipulate and field-strip the pistol. There is a Picatinny rail to mount a laser or tactical light.

The slide is modern, looking like a CNC programer was given free rein. There are three oblong slots on the left- and right-hand sides of the slide and one lone slot on the top. There are also front and rear serrations that make manipulating the slide easy and secure. The slide is tapered on the sides toward the muzzle to relieve more metal, and the very front where the barrel protrudes to is also relieved of metal. No doubt some of the added weight from the SIG Sauer’s frame was displaced by these slide cutouts.

The sights are SIG XRAY 3 Day/Night sights, which feature three-dot tritium inserts. The front-sight dot is larger than the two rear-sight dots. We like the contrast. Just forward of the rear sight is the optics mount cover. Remove the cover to see the slide is cut for a Delta Point Pro, Trijicon RMR, or SIG’s own ROMEO1Pro without the need for an adapter plate.

We were pleasantly surprised to find our best group at the range measured 0.6 inches with the Remington Golden Saber 147-grain BJHP ammo. The Defender 115-grain FMJs were not far behind, with a best group that measured 0.9 inches. Holes grouped in two- and three-shot clusters and in some cases, one ragged hole. This was due to the ease of use, nice grip and trigger, good sights, and perhaps our dumb luck. If it is luck, we’ll take it, because we like this SIG a lot. Going full speed in the Failure Drill, our first two shots were quick and smooth. The full-length metal guide rod helps with the smooth cycling of the pistol, and the metal frame assisted with fast recoil recovery. The more precise head shot on the silhouette target was easy to accomplish. Our team kept going back to the SIG after initial testing because it was so easy to shoot well.

Reloads were smooth due to the magwell and fine tapered double-stack SIG steel magazines. The mags are fitted with aluminum base pads made by the Henning Group, which are checkered for not slipping when slamming them home with the palm of your hand.

Our Team Said: In our opinion, the P320 AGX Pro changed our mind about the P320 model. This pistol is well suited as a competition pistol and defense gun. While it is full size, making it more difficult to carry, we’d trust it with our life because it was so easy to shoot well. The X-Series trigger module and aluminum grip module work well together. This gun is expensive, but in our opinion, it is worth it. It’s Our Pick.

9mm Luger Range Data

Value Guide: 9mm Luger Handgun Rankings