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)
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.
|Action||Semi-auto, short recoil-operated locked breech, striker fired|
|Trigger||Double action only|
|Overall Length||8.1 in.|
|Overall Height||5.7 in.|
|Maximum Width||1.5 in.|
|Weight Unloaded||35.4 oz.|
|Weight Loaded||42.7 oz.|
|Barrel||4.7 in.; 1:10-in. twist|
|Slide Retraction Effort||16.0 lbs.|
|Frame||Hard coat anodized, stainless steel|
|Frame Front Strap Height||2.6 in.|
|Frame Back Strap Height||3.6 in.|
|Grips||Textured G10, black|
|Grip Thickness (Maximum)||1.2 in.|
|Grip Circumference (Maximum)||5.6 in.|
|Front Sight||X-RAY3 3-dot night, green dot|
|Rear Sight||White two-dot notch; optics ready|
|Trigger Pull Weight||4.5 lbs.|
|Trigger Span||2.7 in.|
|Magazines||2; steel w/aluminum base pad|
|Safety||Striker safety lock; disconnect safety|
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
|Defender Remanufactured 115-grain FMJ||RIA STK100||SIG Sauer P320 AXG Pro||Kahr K9||Interarms P-08 Luger|
|Average Velocity||1115 fps||1153 fps||985 fps||1114 fps|
|Muzzle Energy||318 ft.-lbs.||340 ft.-lbs.||248 ft.-lbs.||317 ft.-lbs.|
|Smallest Group||1.49 in.||0.90 in.||1.55 in.||2.05 in.|
|Average Group||1.59 in.||0.96 in.||1.72 in.||2.36 in.|
|Remington Golden Saber 147-grain BJHP||RIA STK100||SIG Sauer P320 AXG Pro||Kahr K9||Interarms P-08 Luger|
|Average Velocity||1014 fps||1016 fps||900 fps||1013 fps|
|Muzzle Energy||336 ft.-lbs.||337 ft.-lbs.||264 ft.-lbs.||335 ft.-lbs.|
|Smallest Group||1.30 in.||0.65 in.||2.45 in.||1.50 in.|
|Average Group||1.52 in.||1.40 in.||2.69 in.||1.51 in.|
|Armscor 124-grain FMJ||RIA STK100||SIG Sauer P320 AXG Pro||Kahr K9||Interarms P-08 Luger|
|Average Velocity||1067 fps||1090 fps||910 fps||1068 fps|
|Muzzle Energy||314 ft.-lbs.||327 ft.-lbs.||228 ft.-lbs.||314 ft.-lbs.|
|Smallest Group||1.88 in.||1.65 in.||2.00 in.||1.62 in.|
|Average Group||1.84 in.||1.85 in.||2.13 in.||1.64 in.|
Value Guide: 9mm Luger Handgun Rankings
|SIG Sauer P365 365-9-BXR3 9mm Luger, $599||Dec. 2021||A||Our Pick. Small enough to fit in a pants pocket. Carries 10+1. Felt recoil is less than with a 38 Sp.|
|Ruger MAX-9 No. 3500 9mm Luger, $544||Sep. 2021||A||Our Pick. This is a sophisticated pistol. No fault with the magazines, capacity, or general accuracy.|
|Smith & Wesson M&P9 Shield Plus 13246 9mm Luger, $553||Sep. 2021||A||A step up from a previously 9mm Shield. The new pistol has an improved trigger and greater capacity.|
|Taurus GX4 1-GX4M931 9mm Luger, $398||Sep. 2021||A-||Best Buy. The Taurus is the most compact, and the Taurus is the only pistol with a changeable backstrap.|
|Smith & Wesson M&P9 Shield EZ 12437 9mm Luger, $479||Feb. 2021||A-||The Shield EZ9 was easy to manipulate and soft to shoot, but the sights needed to be calibrated better.|
|KelTec PF9 Blued-Black 9mm Luger, $358||Feb. 2021||B+||An inexpensive pistol that functioned flawlessly. It reminded us of a good 38 Special snubbie.|
|Taurus G3C 1-G3C931 9mm Luger, $306||Feb. 2021||B+||Best Buy. The Taurus G3C pistol is an inexpensive offering that functioned flawlessly and shot well.|
|Springfield Armory Hellcat HC9319BOSP 9mm Luger, $550||Mar. 2020||A||Our Pick. An 11+1 pistol, this small Springfield might be the most versatile pistol in the group.|
|Walther PPS M2 2805961 9mm Luger, $649||Mar. 2020||A||Best Buy. A smaller pistol with grips that will not abrade tender hands.|
|Ruger Security-9 Compact Model 3818 9mm Luger, $309||Feb. 2020||B||The pistol is adequate for the task of self defense and will not break the bank.|
|SIG P365 Nitron Micro-Compact 9mm Luger, $465||Feb. 2020||B||The SIG costs more than the Ruger Security-9 without overwhelming advantages.|
|Springfield Hellcat Micro-Compact 9mm Luger, $500||Jan. 2020||F/A||Hellcat #1 failed when the trigger wouldn’t reset (F). Hellcat #2 worked perfectly (A). Best accuracy.|
|Glock 43X Ameriglo Night Sights PX435SL301AB 9mm Luger, $542||Jul. 2019||A||Our Pick. Firing grip is superior to the G43 and allows better shooting with little compromise.|
|Mossberg MC1sc 89001 9mm Luger, $365||Jul. 2019||A-||Best Buy. The Mossberg 9mm gave up little to the Glock designs. Reliability was never a question.|
|Taurus G2S 1-G2S931 9mm Luger, $204||Nov. 2018||A||Best Buy. The Taurus pistol was reliable and controllable in rapid fire.|
|Smith & Wesson M&P9 Shield SW180021BW 9mm Luger, $400||Nov. 2018||A||The Battleworn Shield is reliable, accurate enough, and compact enough for EDC.|
|Bersa BP9MCC 9mm Luger, $295||Nov. 2018||A-||Reliable, feels good in the hand, and offers excellent handling in fast-paced drills.|
|Honor Defense Honor Guard HG9SCF FIST 9mm Luger, $400||Nov. 2018||A-||The FIST option is viable. We tested it against barricades with excellent results.|
|Ruger EC9s 3283 9mm Luger, $231||Nov. 2018||B-||Most accurate handgun of the test, despite its light weight.|
|Kimber Micro 9 Desert Tan (LG) 3300168 9mm Luger, $659||Oct. 2017||A||The laser grip complements the large sights on this micro pistol. Edges are smooth for concealed carry.|
|SIG Sauer P938 Emperor Scorpion 9mm Luger, $639||Oct. 2017||A||With large sights, a crisp trigger and toothy grips, this was easy to shoot and control.|