The Korth Mongoose isn’t just another double-action revolver; it’s a statement born of partnership. This premium wheelgun represents the joining of two firms that know quality: Nighthawk Custom of the US and Korth of Germany.
Nighthawk teamed up with Korth to bring their legendary, hand-built German artistry to the American market. This review focuses on the Mongoose—you’re getting an extraordinary .357 Magnum and a 9mm sixgun in one package, thanks to two easily exchangeable cylinders.
Nighthawk Custom and the Korth Partnership
Nighthawk Custom of Berryville, Arkansas, is renowned for fine 1911 pistols built to a high standard of excellence. Each gun is made by one of their highly trained gunsmiths, and every part is hand-fit by that artisan. The finished product is perfect in every detail.
Team Nighthawk knows quality; it’s what they do. Not only do they make some of the best of the best in the firearms world, but they are also nice folks to boot. In 2016, they teamed up with Korth to bring their legendary German-manufactured double-action revolvers to the American gun market.
German Engineering and Key Features
These fine revolvers have been around since 1954. Like Nighthawk Custom pistols, each Korth revolver is hand-built by one gunsmith. They are built with hammer forged precision barrels of 416 R material and include features like fast-change front sights, high-speed hammers, adjustable-from-the-outside main springs, Diamond-Like-Coating (DLC) finish (on this gun), and other quality finishes.
Korth Mongoose Specs
| SPECIFICATION | DETAILS |
| Barrel Lengths | 2.75″ / 3″ / 4” / 5.25” ($100 upgrade) / 6” ($200 upgrade) |
| Weight | 33.6 oz. |
| Overall Length | 8.86” |
| Width | 1.54” |
| Finish | DLC Coated Black |
| Height | 6.1” |
| Caliber | .357 Magnum, Optional 9mm Interchangeable Cylinder |
| Barrel Material | 416R |
| FEATURES | DLC Finish, Hammer-Forged Precision Barrel, Fully Adjustable Rear Sight, Single & Double Action Trigger, New Style Korth Cylinder Release, Easy Reload Through Wide-Swinging Cylinder, Optional Interchangeable Cylinder in 9mm |
Caliber Versatility: The Easy Exchange Cylinder
The easy exchange cylinders on the Korth Mongoose allow the shooter to switch from .357 Magnum to 9mm in a matter of seconds by simply pressing and holding the crane lock located forward and above the trigger guard and pushing the opened cylinder forward.
Trigger and Action Adjustability
The shooter can easily adjust the double action pull of the gun by loosening the left-hand locking screw on the left side of the side plate, aft the trigger guard, and then simply turning the rebound pin on the opposite side of the revolver.
The main spring is adjustable with a hex key. Some grips allow for this to be done without removing them, others require grip removal. Korth’s instruction manual provides clear photos on performing these tasks
Appearance and Detailed Aesthetics
As you can see, the Mongoose has traditional looks, like an L-frame Smith & Wesson. The full-lug barrel of this four-inch gun balances well. The ventilated barrel rib is reminiscent of Colt’s Python. Korth also offers guns that are tricked out with barrel vents and Picatinny Rails. We’ll cover their NXR 44 Magnum in a future article, so if you want a high-end version of their revolver for tactical or competition applications, stay tuned.
Fit and finish are perfect. The (DLC) offers enhanced durability, improved resistance to corrosion, reduced friction, and lubricity. It gives a matte-black-no-nonsense look to the revolver that I find appealing.
The front sight is one of my favorites with a 14K gold bead. Not only is the bead quick to pick up for fast shooting, but it also adds a little something extra in the way of color versus a black front sight. This is a benefit in low light and for aging eyes. The rear sight is adjustable and serrated across the face. These combinations offer a good sight picture.
The smooth-faced, polished trigger is narrow and perfect for my taste. The short double action (DA) pull is a buttery smooth 8 pounds, allowing for fast, and most importantly, accurate shots. The single-action (SA) pull is crisp at about 2.5 pounds.
The stocks, or grips, of this gun are Hogue’s smooth Pau Ferro with finger grooves. They are thin with a bit of palm swell and fit my hand perfectly. There are other options available on Nighthawk’s website should you want a different configuration, higher-grade wood, or even grips of different colors.
Cylinder lockup is bank-vault tight. The appearance of the large cylinder release takes some getting used to, but it is easy to manipulate with a simple forward push.
Range Performance and Accuracy Testing
Groups for accuracy testing were fired from a sandbag rest at 30 feet. I rested my wrists over the bag, and while this is steady, it is not as rock-solid a shooting rest as it would be from a Ransom Rest. While this revolver produced good accuracy, the groups are more an illustration of the shooting ability of this writer versus the pinpoint accuracy of the gun. I think the Korth shoots better than I do!
A three-shot target fired at 12 yards was supplied with the gun, and it’s a nice, tight cloverleaf group. A couple of my groups depicted a bullet going in the same hole as a previous shot. I’ll take that type of accuracy all day long. Consequently, a couple of other groups were widened by a flyer pulled by yours truly. Those are on me, and not the revolver.
Caliber Performance and Data
To measure the groups, I used a digital caliper to measure the outside edge of the farthest bullet holes of each six-shot group and subtracted the bullet diameter, with the exception of a called flyer while shooting the High Desert Cartridge Company 158 gr JHP 357 load. I saw no need to count that errant shot. It measured just 0.71 inches.
In the 9mm cartridges, Hornady’s Backcountry Defense round grouped a tight 0.73-inch. Their Critical Defense load was just as accurate at 0.75”. All groups in 357 Magnum (one 38 Special) averaged 1.31 inches and groups fired through the 9mm cylinder averaged 1.18 inches.
Ammunition Compatibility Notes
Buffalo Bore Ammunition is known for being stout and all business. At this point in my career, I think I could determine (by feel) when I’m shooting their good ammunition by the authority of the cartridge being fired from handguns, while blind folded!
Recoil, power, whatever we call it, Buffalo Bore is all there, even with standard pressure loads. The three 9mm loads provided by them all shot well in this revolver; however, they produced very sticky extraction of the fired cases. Their powerful, higher-pressure 9mm loads are not for this specific gun. Perhaps polishing the chambers would resolve the issue. If it were my gun, I would investigate that option further and discuss the procedure with Nighthawk, as often I rely on Buffalo Bore’s ammo in my personal guns.
None of this is intended to be derogatory about the gun or the ammo; it’s just fact and a reminder to shoot plenty of what you will be carrying to make certain the gun and ammunition mesh well together. There were no extraction issues with Buffalo Bore’s heavy .357 Magnum load.
Shooting and Handling
Stepping away from the bench, it was time to take on the steel at 40 yards. With the smooth DA pull, the pleasing clank of metal echoed back from the torso-sized plates. This is where the beauty of the 9mm cylinder shines. Recoil is minimal from the revolver, even with the warmer 9mm loads.
Running some Herter’s FMJ Target Loads for fun was, well, a lot of fun! Remington’s Performance WheelGun .38 Special load was used in similar fashion from the .357 cylinder. I shot the steel a bit with the higher-end loads, but performance ammunition provided by the manufacturers is expensive, and I tend to save it for accuracy tests, future reviews, and business, like defensive carry and hunting.
The Verdict: Is the Korth Mongoose Worth the Investment?
Many will ask, “Why spend so much money on a revolver, and are they worth it?” I’m not a paid spokesman for Nighthawk or Korth, and no, they aren’t giving me a gun. If I want to keep it, it’s going to cost some real dinero and a very careful and well-thought-out explanation to my wife! My answer to those questions is yes, and here are my justifications.
A quality custom revolver like this is not cheap these days. Guns in general are expensive, with some stock DA revolvers ranging from $1200 to $1800. Oftentimes, an action job will need to be performed by a gunsmith to get the trigger pulls where we want them. It’s not uncommon to need to replace a front sight to gain proper sight height. Add in parts, labor, and shipping costs and those “less expensive” revolvers rapidly increase in value.
A gun built to exact specifications with quality parts exhibiting superb fit and finish takes a lot of time and skilled labor. Many of the finer things in life cost a lot of money. A hand-cut, dry-aged beef steak, top-shelf bottle of whiskey, pure beaver felt hat, handmade boots, custom knife, you name it, the best of anything is not cheap.
I’ve recently received a Cliff Notes education on high-end watches from a friend who was bitten by the watch bug. Several thousand dollars gets one’s foot in the door of these time-telling devices of note. Having enough expensive hobbies in the form of guns and hunting, I quickly dismissed his selling points and will stick with my cheap timepiece!
Korth’s revolvers easily fit into this category of high-end artistry and craftsmanship.
Every part is machined from billet steel, and each revolver undergoes 10 to 14 hours of hand fitting and polishing to bring them up to the thorough standards that are evident when holding these fine guns. Recent import tariffs have raised the cost of the gun by $350.00, so this revolver is now selling in the neighborhood of 4K.
In a way, with this Mongoose, we are getting two guns for the price of one. An extraordinary .357 Magnum and a 9mm sixgun in one package we can pass down to the next generation of shooters to be enjoyed long after we’re gone.
Smoothness. Accuracy. Dependability. Value. Korth has all of that. I’ve provided the justifications, now you just have to decide if you want to make the investment!
| AMMUNITION | GROUP |
| .357 Magnum/.38 Special | |
| Buffalo Bore 19D 125 gr JHC, 1700 fps | 1.88” |
| High Desert Cartridge Co. 158 gr TMJ, 993 fps | 1.2” |
| High Desert Cartridge Co. 158 gr JHP | 0.71” (excluding called flyer) |
| Hornady Handgun Hunter 130 gr MONOFLEX, 1250 fps | 1.34” |
| Hornady 38 Special American Gunner, 125 gr XTP, 900 fps | 1.41” |
| 9mm | |
| Buffalo Bore 24F, 9mm Luger +P+ Penetrator, 124 gr FMJ-FN, 1300 fps | 1.42” |
| Buffalo Bore 24, Subsonic Heavy 9mm, 147gr JHP, 1000 fps | 1.26” |
| Buffalo Bore 24L, 9mm +P Outdoorsman, 147gr Hard Cast FN, 1100 fps | 1.11” |
| High Desert Cartridge Co. 9mm 115 gr TMJ, 1135 fps | 1.21” |
| Hornady Backcountry Defense 9mm Luger +P, 138gr DGH, 1150 fps | 0.73” |
| Hornady Handgun Hunter 9mm Luger +P, 115gr MONOFLEX, 1100 fps | 1.51” |
| Hornady Critical Defense 9mm Luger, 115 gr FTX, 1135 fps | 0.75” |
| Hornady Subsonic 9mm, 147 gr XTP, 975 fps | 1.42” |
