Gun Test: Ruger GP100 10mm

The story of revolvers chambered for self-loading cartridges is a long one. Smith and Wesson and Colt supplied revolvers chambered for the .45 ACP revolver cartridge during World War I. The .455 Webley caliber double action revolvers in production for the British were re-chambered to .45 ACP and a moon clip was developed to allow chambering the rimless .45 ACP.

Since the .45 ACP doesn’t have a cartridge case rim, moon clips were necessary for proper headspace. Revolvers chambered for an automatic pistol cartridge will chamber and fire the cartridges OK, but they will not eject. Revolvers have been chambered in .380 ACP, .38 Super, 9mm, .40, 10mm, and .45 ACP. Sometimes they work well, but they are always interesting nonetheless.

Ruger’s GP100 is a rugged, reliable, and accurate revolver that has been chambered in .357 Magnum, .44 Special, and a few other calibers. It was logical to chamber the piece for the 10mm Auto. The Redhawk 10mm, however came first; the GP100 is more practical.

The 10mm is a popular cartridge, and the GP100 has promise. The 10mm is chambered in the Match Champion version of the GP100. The Match Champion features a fiber optic front sight and well designed grips. These wood grips appear larger than the usual factory grips, at first glance, but they are not.

The cross section is actually smaller than standard GP100 grips and fits my average-sized hands well. They are long, which makes for a good fit for larger hands, but they are not thick. The combination of high visibility front sight and fully adjustable rear sight make for excellent hit probability.

The stainless steel revolver features a four-inch barrel. Barrel profile differs from the .357 Magnum and is pleasing in appearance. The action was smooth in double-action fire, and the single action trigger was crisp enough for good accuracy. Due to the larger hole in the barrel and chambers, the Ruger GP100 Match Champion 10mm is lighter than the .357 Magnum version at 37 ounces. It is similar in weight to a Government Model 1911. The revolver is wider and bulkier to conceal than a 1911, but the proper holster goes a long way toward addressing this. On the hip, on the trail, or in home defense, it doesn’t matter how wide the handgun is.

The question might be why the 10mm? The 10mm is readily available, more so than the .41 Magnum. Recoil is modest compared to magnum cartridges and the 10mm offers good performance at long range. While it isn’t a magnum, the 10mm is a respectable number proven in the field. As an example, the Hornady 180-grain XTP, a great all around field and defense load, clocks 1,180 fps from the Ruger’s four-inch barrel. The fast stepping 155-grain XTP breaks 1,402 fps. This would be the preferred 10mm load for personal and home defense in my opinion. The Hornady 175-grain Critical Duty is designed for service use. At 1,102 fps this is another hard hitting load that offers an excellent balance of expansion and penetration.

During the initial evaluation of the GP100 10mm, I used SIG Sauer Elite full metal jacket ammunition. This is an affordable loading supplied in 50-round boxes. It burns clean and is quite accurate.

I fired 50 rounds, simply loading the cartridges individually and picking them out with a pencil rather than using moon clips. I fired at man-sized targets at 5, 7, and 10 yards, firing in the double action mode. The Ruger GP100 10mm comes on target quickly. It is well balanced and the fiber optic front sight is an aid in rapid sight acquisition.

Getting center hits quickly isn’t difficult for those who understand how to press the trigger, allow the piece to reset during recoil, and then press again. There were no malfunctions of any type. Next, I loaded a number of the SIG Sauer V-Crown hollow points in Ruger’s supplied moon clips. Loading was fast and positive. I fired three full moon clips as quickly as possible with excellent results. The targets were riddled in the X-ring, and the moon clips provide excellent speed.

An advantage of moon clips in loading and unloaded compared to conventional revolvers is that spent cartridge cases are easily ejected whether the barrel is pointed upward or downward. You need not be concerned with a cartridge case rim becoming trapped under the ejector star. When loading the revolver with moon clips, loading is fast and positive. Keep the fingertips near the front of the cartridge and guide them into the chamber then, press the six cartridges home. This is one fast combat revolver.

Recoil ranges from modest to stout with full power 10mm loads. As an example, the fast stepping Hornady 155-grain XTP breaks 1,402 fps from the Ruger—50 fps more than from a five-inch 1911. The piece is an ounce lighter than a .357 Magnum revolver. Most 158-grain .357 Magnum loads break about 1,250-1,300 fps. So, recoil must be greater than the .357 Magnum with standard loads.

While it is generally stated that the .357 Magnum cartridge is more powerful than the 10mm with modern loads, the 10mm is comparable to, or even more powerful than, the .357 Magnum—figures do not lie. It depends to an extent on the loading. As another example, the Hornady .357 Magnum 125-grain XTP breaks 1,400 to 1,420 fps in most four-inch barrel revolvers, while a 180-grain hard cast bullet .357 Magnum handload that I had on hand would break at 1,320 fps in a four-inch barrel. Much depends on the load and the shooter’s skill, but clearly the 10mm is a powerful number. In close range personal defense, the 10mm begins at .40 and will punch a large hole whether the bullet expands or not. The 10mm offers plenty of horsepower for personal defense and hunting thin-skinned game to at least 50 yards. I believe this revolver would be a great boar gun.

I was able to fire several loads from a solid benchrest for accuracy. The 10mm revolver gave respectable results at a long 25 yards. With attention to the front sight and proper sight picture and alignment—and careful trigger compression—I was able to secure several five-shot groups of 1.85 to 2.65 inches. While the .357 Magnum GP100 is generally more accurate, the 10mm is more than accurate enough for most chores. The advantage of the moon clips in competition and personal defense is obvious. The GP100 fits my needs well. This revolver will be fired often and carried on the hip or in a shoulder holster in the field.

The .40 S&W Option

The revolver properly headspaces the 10mm automatic pistol cartridge on the case mouth. .40 S&W ammunition is dimensionally fine and pressure-wise safe, but will simply fall into the cylinder if you load it without moon clips. The Ruger moon clips invite .40 caliber use. They are sturdy and do not demand a special tool for loading. Ruger’s new design for the moon clips makes their use easy enough, a great improvement over previous types.

I fired more than 100 .40 S&W cartridges in the Ruger. Recoil is much more pleasant than the 10mm. A 180-grain JHP at 980 fps simply doesn’t generate a lot of recoil. They are a fine under study to the 10mm. Just the same, the .40 S&W option is a respectable defense load. While it doesn’t have the gee whiz of the more powerful 10mm, the .40 will do the business in personal defense. Control is good and while accuracy isn’t quite up to the 10mm at self-defense distances, this is a good option.

As an example, the Hornady 155-grain XTP breaks 1,140 fps from the GP100’s four-inch barrel. This is a great personal defense load, but far easier to control than the 10mm. In some ways, this is similar to the difference between the .38 Special and the .357 Magnum in similar revolvers. However, in this case, the less powerful .40 S&W is well suited to personal defense and offers excellent wound potential. In power, the .40 S&W is similar to better than the old .38-40 revolver cartridge. At present, I may have but scraped the surface of the versatility of the 10mm revolver.

Ruger GP100 and full power 10mm loads—What’s not to like about that combination? Are you a big bore revolver fan? What is your favorite revolver and caliber combination? Share your answers in the comment section.

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