Korth Mongoose DA/SA Centerfire .357 Magnum Revolver

The Korth Mongoose double-action/single-action centerfire .357 Magnum is an ultra-premium, precisely engineered wheelgun for those with means.

January 17, 2024 By Brad Fitzpatrick

In an era when most handgun manufacturers are concentrating their efforts on producing affordable polymer-frame semiauto pistols, a custom-built German wheelgun like the Korth Mongoose with an almost $4,000 price tag stands out from the crowd. But Korth’s Mongoose revolver stands out for all the right reasons and offers a level of quality that cannot be achieved through mass production. The Mongoose isn’t for everyone, but for those who appreciate fine revolvers, Korth guns are the benchmark.

Korth has been in business since 1954, but for years the brand was barely known outside of Germany. That changed in 2016, however, when Korth selected Arkansas-based Nighthawk Custom to be the sole U.S. importer of its revolvers. For the first time these guns were widely available in the American market, and since then more and more shooters have come to appreciate just how good Korth guns really are.

Landon Stone of Nighthawk Custom told me the partnership between Nighthawk and Korth was ideal because both companies had the same philosophy of using premium hand-fitted machined parts, and both companies stand behind their products.

Korth Mongoose cylinder release latch — The Korth cylinder release latch is located just to the left of the hammer. Pressing forward releases the cylinder, which makes it easy—and fast—to top off the gun with a speedloader.

In fact, Nighthawk is backing Korth revolvers with a lifetime guarantee, and even has a Korth-trained gunsmith in its Arkansas facility who works on these guns. Anytime a brand offers a lifetime warranty on another company’s product you can bet you’re getting the very best.

The Mongoose features all the Korth trademarks that fans of the brand have come to love and demand. Chief among these are the coil mainspring and roller trigger, which is incredibly smooth and even throughout the pull.

The test gun had a three-pound, three-ounce single-action pull weight, and the trigger broke cleanly and smoothly. Double-action trigger pull was eight pounds, four ounces. The trigger reset on the Korth is very short, so you can fire this gun more quickly and accurately in double-action mode than most competing revolvers. Best of all, the Korth’s trigger is adjustable using the provided tool.

Another characteristic of Korth guns is the oversize cylinder release located just to the left of the hammer. The release is round and serrated and has a diameter of 0.39 inch. It’s plenty large enough to locate and operate when you need to reload quickly, but it stays well clear of the shooter’s fingers when shooting single action. The hammer passes extremely close to the release, and there’s probably no more than a few hundredths of an inch of space between the two during operation, but the two do not interfere with one another.

Another feature unique to Korth revolvers is the push-button cylinder assembly removal catch on the gun’s right-hand side. Pressing the spring-loaded button moves the lug that locks the crane in position in the frame so the cylinder slides forward and free from the frame. Replacing it is just as simple, and Nighthawk offers an optional 9mm Luger cylinder. Swapping the .357 Magnum and 9mm cylinders takes a matter of seconds.

The Korth Mongoose 3-inch model comes with notch sights. — The adjustable notch rear sight on the three-inch version is carry friendly, while models with longer barrels offer target-style rear sights.

Korth offers 9mm cylinders cut for moon clips, as well as an innovative and effective “clipless” design. With the clipless cylinders, extractor extensions engage the 9mm rim and provide the bite needed to remove the case from the cylinder.

Each cylinder is fitted to the individual revolver so function is flawless and extraordinarily smooth. The addition of a custom cylinder runs about $1,400.

The Mongoose is the most austere of the Korth revolvers currently available through Nighthawk. These guns don’t feature the barrel weights or vented shrouds you’ll find on the NXS and NXR models, nor do they sport color case-hardening such as you’ll find on the Vintage .357 Magnum.

But this gun’s understated looks don’t mean it lacks premium components. The Mongoose is full of Teutonic precision parts, including Korth’s signature roller-style trigger that uses roller wheels to engage the sear for a smooth, seamless double-action trigger pull.

Every machine cut is precise and smooth, including the machining on the ratchet that engages the pawl while firing. Cylinder lockup fore and aft is rock solid, and even the hammer spur is precision machined. The gap between the cylinder and barrel is so tight you’ll have to hold the pistol just right to see daylight between them.

Everything is hand-fitted and custom tuned both in Germany and at Nighthawk in the States, so guns are inspected and tested before they leave the facility in Arkansas. Any revolver that doesn’t meet Nighthawk’s high standards doesn’t get out the door.

Korth uses the finest precision-machined billet metal parts. Martin Rothman, who has been an owner at Korth since 2009, specialized in precision billet steel components for the automotive industry. His parts were used in the production of Lamborghini, Ferrari, Porsche, Rolls-Royce and other premium automobiles. Hand-fitting ensures Korth guns operate like a fine Swiss watch.

The Mongoose is available with 2.75-, three-, four-, 5.25- and six-inch barrels (the latter two at extra cost), all of which are hammer forged and have a low-gloss matte black DLC finish.

The Korth three-inch Mongoose I tested features a fully adjustable black rear notch sight and a 14-karat gold bead front sight. The Mongoose’s serrated topstrap and vent rib reduce glare.

The gun weighs 35 ounces. With a height of 6.1 inches, an overall length of 7.9 inches and a maximum width of just over 1.5 inches, the Korth could be a carry gun. It’s similar in size to Colt’s three-inch Python .357, although the Python weighs a couple ounces more and is slightly wider and longer.

Korth Mongoose .357 Magnum Revolver cylinder is easily removed and switched for 9mm options — Removing the cylinder takes a matter of seconds, and the Mongoose offers two optional 9mm cylinders—one cut for moon clips and one clipless.

Handguns protocol calls for testing guns with three-inch barrels at 15 yards, and that’s where I started with the Korth. It was printing one-inch groups, and I decided with its precision manufacturing and high-end components like a cold hammer-forged barrel and crisp, adjustable trigger—not to mention a price tag over $3K—I should test it at 25 yards, too.

At that distance the Korth managed groups as small as 1.9 inches for five shots, with averages in the neighborhood of 2.5 to 3.5 inches. These results are shown in the accompanying table.

But to fully appreciate this gun it must be tested off the bench, and that’s exactly what I did. From seven yards the Mongoose placed all five shots on or just outside the X-ring of a torso target in double action.

Some factory revolvers won’t do that in single action, and it speaks to how well the Korth—and particularly its trigger—is designed. In one of the tests, three of the six shots were actually touching when fired double action.

It’s worth noting, though, that this gun has really tight tolerances. This translates to outstanding accuracy, but there’s a trade-off.

Korth Mongoose .357 Magnum Revolver Shot Group — A six-shot group fired double action at seven yards, with three rounds actually touching, shows how well such a finely tuned revolver can shoot.

After about 150 rounds I noticed the gun was not operating as smoothly in double-action mode. It wasn’t an issue with the gun itself but rather a buildup of fouling that was interfering with cylinder rotation. It never prevented the gun from firing, but I could feel the cylinder rotating more tightly when I allowed fouling to build up. That was an easy fix, though: a quick wipe down, and the gun was as good as new.

As a fan of revolvers I must say that the Mongoose, and every other Korth gun I’ve shot, is a joy to have at the range. Everything on this gun is smooth and elegant, from the ultra-tough and understated DLC coating to the contrasting high-polish components like the hammer and trigger. It seems odd that Korth has paired it with a basic Hogue grip, which seems a bit utilitarian for a gun of this ilk. Nevertheless, it’s really good.

The way I describe these guns to other shooters—who invariably ask if they’re worth the money—is that imagine your favorite double-action revolver was given to the world’s top gunsmiths for fine tuning, and that every component of the gun was replaced by a premium machined part.

If you sent a $1,500 revolver in for such a treatment, you’d probably have at least $3,000 in the revolver when the work was finished, and perhaps even more. It’s only then that the Korth’s price begins to make sense to some shooters. You simply aren’t going to replicate a Korth level of quality and performance on a shoestring budget.

In a world overflowing with sub-$500 semiauto 9mm pistols, a high-end revolver is something of an oddity. But if you’re a fan of revolvers like I am, you can’t help but appreciate the craftsmanship that goes into building a world-class revolver. And what I like most about Korth is that the brand believes the classic wheelgun design is worthy of the royal treatment. When it comes to premium revolvers, Korth remains the king, and thanks to Nighthawk you can get one.