Palmetto State Armory 5.7 Rock

David Freeman

I have become a fan of the 5.7x28mm cartridge as the result of reviewing pistols in that caliber by FN Herstal, Ruger and Smith & Wesson. Palmetto State Armory released a 5.7x28mm pistol a couple of years ago. That one, called the “Rock,” is the subject of this review.

Palmetto State Armory Rock 5.7
The Palmetto State Armory Rock 5.7×28 Caliber Pistol

The 5.7x28mm came about as a result of NATO seeking a 9mm replacement with greater range and accuracy and the ability to penetrate body armor. FN Herstal designed a cartridge to meet the NATO requirements and built a gun that would shoot it. The new FN 5.7x28mm cartridge featured a 1.138-inch-long case with a rebated rim and a 35-degree shoulder designed for a .22-caliber bullet weighing anywhere from 23 to 31 grains. Obviously it’s a much smaller projectile than the 9mm, but what it lacks in size it makes up for in velocity. Shot through a long barrel, the cartridge drives a 26-grain slug at a velocity of nearly 2,400 feet per second, about 2.5 times faster than typical 9mm loads. The size of the projectile has evolved so we’re now shooting 40 grain most often and there are even 5.7x28mm rounds with 62 grain projectiles. These larger bullets are slower, traveling in the 1650 to 1799 fps range.

FN’s first two guns to shoot the cartridge were the FN P90 PDW (Personal Defense Weapon), along with the FN Five-seveN pistol. The Five-seveN became an immediate hit with some militaries, law enforcement agencies and sport shooters, but its price kept many potential firearm buyers away. All of this happened in the latter part of the 1980’s. In recent years, several firearms companies have designed new guns around the 5.7 cartridge causing somewhat of a rebirth in interest among shooters which led to more companies giving the cartridge a try. 

Ruger somewhat surprised the market with its 2019 introduction of the Ruger 5.7. Featuring a 4.9-inch, alloy steel barrel with a nitride coating for wear resistance, the full-size pistol has a lot going for it. Impressive ergonomics include an easy trigger reach, robust slide release and reversible magazine release latch. The hardened, billet steel slide with lightening cuts is drilled and tapped for easy mounting of optics with separately available optic adapter plates.  The Ruger 5.7 ships with two 20-round steel magazines and is priced several hundred dollars below the FN pistol.

At this year’s SHOT Show, Smith & Wesson announced it was jumping into the 5.7 game. The M&P line now includes the M&P 5.7. The M&P 5.7 uses a newly designed internal hammer-fired, gas-operated, locked-breech barrel system in which the barrel doesn’t cam open until the bullet passes the gas port for what the company calls “worry-free consistency.” The polymer-framed, full-size pistol features a 5-inch barrel to utilize as much of the cartridge’s potency as possible. It comes optics-ready and with a threaded barrel for use with a suppressor if desired. Capacity is 22+1 giving it a bigger ammo payload than similar-size 9mm pistols. I’ve previously covered the Ruger 57 and the S&W 5.7 here on the Shooter’s Log.

Palmetto State Armory’s 5.7 offering is similar in size and capacity to the Ruger and the Smith & Wesson. As best I can tell from studying PSA’s website, the Rock is available in 52 different configurations. The one I have is the 5.7 Rock Black Standard. It has a black frame, non-treaded barrel and 3-dot day sights.

This is the PSA Rock Standard Model

The PSA 5.7 Rock is a striker-fired, polymer-frame handgun designed to maximize capacity with the small FN cartridge. It can be had in an optics-ready configuration with a milled slide cut for the Shield footprint, and open-sighted models with night sights are available that accept Glock-pattern sights.

Externally, the PSA 5.7 Rock is highly similar to the Ruger-5.7 and the S&W M&P 5.7. All three guns have a Picatinny accessory rail on the frame, front and rear slide serrations, extensive texturing throughout the grip frame, blade trigger and a magazine capacity of 20 or more rounds.

They are very similar in size:

 LengthHeightWidthWeightBarrel LengthCapacity
PSA8″5.2″1.2″25 oz.4.7″23+1
Ruger8.65″5.6″1.2″24.5 oz.4.94″20+1
S&W8.5″5.25″1.1″26.7 oz.5″22+1

Here are specs for the Rock as listed on the Palmetto State Armory website:

  • Model: PSA Full Size 5.7 Rock
  • Caliber: 5.7x28mm
  • Capacity: 23+1
  • Weight with Empty Mag: 25 oz.
  • Barrel Material: Carbon Steel with QPQ Finish; Fluted
  • Barrel Length: 4.7″
  • Twist Rate: 1/9″
  • Slide Material: 416 Stainless Steel with QPQ Finish
  • Action: Delayed Blowback Striker-fired
  • Mag Catch: Reversible
  • Safety: Trigger & Striker
  • Accessory Rail: Picatinny
  • Magazine: 23 round Steel 5.7x28mm Magazine (Ships with 2)
  • Designed to work with Glock™ compatible sights
  • Ships in Palmetto State Armory Soft Pistol Case 

Right about now you may be asking, “What’s QPQ?” QPQ stands for “Quench Polish Quench.” It refers to a process used to increase corrosion resistance. Other properties can also be improved by performing the QPQ treatment including: wear resistance; capacity to reduce friction, known as “lubricity,” and fatigue resistance.

I’ve received several guns lately that were shipped in canvas cases. The one from Palmetto State Armory has a pouch for the barrel and Velcro strap for the grip to secure the gun plus pockets for the two magazines and the lock. On the outside front it has a very nice, embroidered PSA Logo with a clear plastic pocket beneath it for displaying ID information such as a business card. Unzipping the case and pulling out the gun for the first time felt a little bit like Christmas morning.

PSA Rock in Canvas Carrying CAse
PSA Rock in it’s Carrying Case With Two Magazines

Although some say the Rock designers stole its look from the Ruger 57, I don’t think so. I find it very attractive in its own right. My first impression when holding the gun in my hand was, “If this gun shoots like it should, this is a gun I will be proud to own.” Naturally I racked the slide to clear the gun, found a good dry fire target on the wall and pulled the trigger. Very nice! I struggle with the slide on some of my 9mm handguns, but the 5.7x28mm doesn’t require a strong spring to cycle the gun; therefore, I can easily rack the slide on any of the 5.7 handguns, this one included.

The size of the 5.7x28mm round is such that the pistol grip is long and narrow to accommodate. There is a high undercut on the trigger guard allowing a high grip on the frame. The trigger reach is such that even my short, stubby fingers have plenty of extra length there. Sights on my gun are the standard three white dot arrangement. The slide has the standard Glock cut for sights making any of a number of aftermarket sights an easy upgrade. Front and rear serrations on the slide are there to assist with any hand position the shooter likes to use for racking slides. The Picatinny rail has three slots, and behind it the trigger guard is squared off in front for those of us who like to put the index finger of the support hand on the front of the trigger guard for stability.

The slide lock lever is small but easy to manipulate and it has a protective ridge around the bottom and front to prevent inadvertent operation during shooting. Unfortunately for South Paws, it exists only on one side. The magazine release button is rectangular in shape and reversible. Its operation is positive, resulting in a nice magazine ejection. The magazine baseplate is slightly larger than the bottom of the grip allowing for an easy grasp to pull out a magazine that may be stuck. Also there is an indention on both sides at the bottom of the grip to facilitate grasping and pulling the magazine out. The texture on the grip and on both sides of the frame where the index finger rests is very comfortable, yet aggressive enough to provide a non-slip grip. There’s a single bump on the front strap positioned to go between your index and middle finger. It makes a secure grasp easy.

Takedown for cleaning is non-standard by very easy.
Follow instructions in the manual for the first time.

Takedown for the Rock is a bit non-standard. After ensuring the gun is unloaded, the trigger pulled and the magazine out of the gun, wrap your firing hand over the top of the slide and pull the slide back until approximately ¼ of it extends toward the back. Don’t go too far or the trigger will reset, and you’ll have to start over. With your support hand, pull the takedown levers that are located above the center part of the trigger guard down on both sides. Release pressure on the slide with your firing hand, allowing it to move forward until the rear of the slide is approximately 3/8 inch forward of the end of the grip. You can then lift the slide off the frame. Remove the recoil spring, then lift the barrel out and that’s it. Reassembly is a simple matter of replacing the barrel and recoil spring, then setting the slide down on the frame, the notches on the slide aligned with the front and rear tabs on the frame, then sliding it rearward until you hear and feel a click. Then rack the slide and you’re done.

One nice thing about loading 5.7 magazines is you simply push the rounds down from the top like you do an AR magazine. I didn’t take the time to load a full 23 rounds but once, but when you’ve got that many rounds in the gun on your hip, you’ve got a pretty good defensive load in my opinion. Speaking of carrying the gun on your hip, the Rock fits easily into any of the holsters I have that were made for the S&W M&P.

First rattle out of the box shooting from ten yards away, I was very disappointed. The Rock was putting all my rounds off to the left of my aiming point and with an unacceptable spread of 5 inches or more. I handed the gun to one of my shooting buddies, and he had the same experience except instead of shooting off to the left, his rounds were going low. I tried loading some rounds from a different box of ammo, and darned if the gun didn’t shape right up and start looking pretty good. Those first rounds were from a box of FN 27 grain ammo. The second load was American Eagle 40 grain ammo. Amazing difference. After shooting that for a while,20 I tried some FN 40 grain ammo, and it also shot well.

Typical target for the Rock, fired offhand at ten yards.

The Rock is a very comfortable gun to shoot—nice trigger, low recoil, acceptable accuracy, right on par with the Ruger and S&W examples I have of 5.7x28mm handguns and at a price below the others. If you’ve not tried a 5.7x28mm pistol yet and want to jump in the game, the Palmetto State Armory Rock is a great place to start. And if one 5.7x28mm is all you’ll be buying, you won’t be disappointed with this one.

Author: David Freeman

Professional dedicated to training and equipping people to live safely in a dangerous world.

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