Compared: The .41 Magnum and 10mm Auto

By Chuck Hawks

The .41 Remington Magnum revolver cartridge was introduced in 1964 to fill the gap between the .357 Magnum and .44 Magnum. It uses a rimmed case of similar length and style to the earlier magnums and accepts .410" diameter bullets. It was designed as a dual-purpose cartridge intended for police and sportsmen (hunters). There were two power levels of factory loads, a full power hunting load and a mid-range police service load.

The full power hunting load advertised a 210 grain jacketed bullet at a muzzle velocity (MV) of 1500 fps and muzzle energy (ME) of 1050 ft. lbs. The mid-range service load advertised a 210 grain lead bullet at a MV of 1050 fps with ME of 515 ft. lbs.

Both turned out to generate too much recoil and muzzle blast for the majority of police officers, who are generally not recreational shooters skilled in the use of powerful magnum handguns. And the large framed S&W Model 58 police service revolver was too heavy and bulky for comfortable all day carry.

The full power .41 Magnum load was alleged to provide ballistics close to the .44 Magnum at reduced recoil. It lived up to the first part of that description better than the latter part. Most shooters found it difficult to tell a .41 Magnum from a .44 Magnum (which, after all, is really a .429 caliber) at either end of the revolver.

Ultimately, the concept of the .41 Magnum as a police cartridge faded and today it is pretty much exclusively used as a hunting cartridge, and a fine one it is. Smith & Wesson and Ruger have always been the main purveyors of .41 Magnum revolvers, although the .41 Magnum has also appeared in a few other revolver brands, as well as the T/C single shot pistol. Unlike the .357 Mag./.38 Special and .44 Mag./.44 Special, the obsolete .41 Colt is not interchangeable with the .41 Magnum cartridge and cannot be used as a low power understudy. A .41 Magnum revolver may be used only with .41 Magnum ammunition.

The 10mm Auto cartridge was introduced in 1983 in the Bren 10 pistol. (10mm is .40 caliber.) This cartridge is based on a shortened, straight walled, .30 Remington rimless rifle cartridge case. The Bren 10 pistol had technical difficulties and was a commercial failure, but the 10mm Auto cartridge was picked-up by Colt for a special model of the M1911 called the Delta Elite. Subsequently it has been adopted by other pistol manufacturers, including S&W and Glock (in their full size Model 20 and compact Model 29).

In 1989 FBI was looking for a new pistol and cartridge and they became interested in the 10mm Auto. Very soon it became obvious that the full power cartridge was too much for the average agent to control, and a reduced power 10mm Auto mid-range load was designed for, and ultimately adopted by, the FBI. The parallel to the earlier .41 Magnum cartridge is worth noting. The FBI chose a double action Smith & Wesson semi-automatic pistol as their new service weapon, which proved to have serious reliability problems.

The high velocity 10mm load advertised a 180 grain JHP bullet at a MV of 1240 fps and ME of 618 ft. lbs. The mid-range (FBI or "10mm Lite") service load advertised a 180 grain JHP bullet at a MV of 950 fps with ME of 361 ft. lbs. This proved to be about right for police purposes.

The technicians at Smith & Wesson realized that the big 10mm Auto case was unnecessary for the reduced power load actually adopted by the FBI, and that they could avoid the technical problems that plagued their 10mm pistol if the cartridge were smaller and the pistol did not have to accommodate full pressure 10mm loads. Smith & Wesson teamed with Winchester to develop the new concept and the result was the .40 S&W cartridge, which has been a big success in the police market as it offers mid-range 10mm performance in a cartridge compact enough to work in pistols designed for the 9mm Luger cartridge. The advent of the .40 S&W cartridge essentially rendered the 10mm Auto obsolete as a police service cartridge. (For more on the .40 S&W see my article "The .40 Smith & Wesson.")

The practical result of all this intrigue was that the popularity of the 10mm Auto was as short lived as the popularity of the previous .41 Magnum revolver cartridge. Both proved too powerful for the police and military markets. The .41 Magnum found a niche as a hunting cartridge, although it has never become very popular, and the last I heard Glock (who has become the main supplier of 10mm Auto pistols) was promoting their full size Model 20 as a hunting self-loader. By the way, unlike the Bren 10 and Smith and Wesson 10mm pistols, Glock 10mm Auto pistols function just fine.

Clearly, as originally introduced, the .41 Magnum was a more powerful cartridge than the 10mm Auto. As I write these words the ballistics of the .41 Magnum have been revised (downward). The Federal Classic factory load is typical and shows a 210 grain JHP bullet at a MV of 1300 fps with ME of 790 ft. lbs. The figures at 100 yards are 1030 fps and 495 ft. lbs., which are still substantial. The mid-range trajectory of that load is 3.3" over 100 yards.

Federal also offers a Premium Handgun Hunting load for the .41 Magnum. This uses a 250 grain CastCore (gas check, hard cast lead) bullet at a MV of 1250 fps with ME of 865 ft. lbs. The 100 yard figures are 1080 fps and 645 ft. lbs. The trajectory of that load looks like this: +0.6" at 25 yards, +1.1" at 50 yards, 0 at 75 yards, and -2.9" at 100 yards. The CastCore bullet was developed specifically for big game hunting; its flat-nose bullet offers deep penetration without fragmentation. These Federal .41 Magnum ballistics were developed in a 4" vented (revolver) barrel, although most .41 Magnum revolvers are sold with 6" or longer barrels.

The Federal Classic 10mm Auto load uses a 180 grain JHP bullet at a MV of 1030 fps and ME of 425 ft. lbs. The figures at 100 yards are 920 fps and 340 ft. lbs. The mid-range trajectory of that load is given as 4.7" over 100 yards.

Federal also offers a Premium load in 10mm Auto. This comes with a 180 grain Hydra-Shok JHP bullet at a MV of 1030 fps with ME of 425 ft. lbs. At 100 yards the figures are 920 fps and 340 ft. lbs. The mid-range trajectory of that load shows a 4.7" rise over 100 yards. These Federal 10mm Auto ballistics were developed in a 5" sealed breech (not vented) barrel.

The .41 Magnum's bullet has an actual diameter of .410" while the 10mm Auto's bullet has an actual diameter of .400" diameter. This gives the .41 Magnum a modest advantage in bullet frontal area and consequently wound channel diameter if other factors are equal.

The 210 grain .41 Magnum bullet has a sectional density (SD) of .178 while the 10mm Auto's 180 grain bullet has a SD of .161. This gives the .41 Magnum a modest advantage in bullet penetration and consequently wound channel depth if other factors are equal. The .41 Magnum thus has the potential to create both wider and deeper wound channels.

With a 270 fps advantage in muzzle velocity, a 365 ft. lb. advantage in muzzle energy, a heavier bullet, greater bullet frontal area, better SD, and a flatter trajectory, there can be no question that the 210 grain .41 Magnum load has potentially greater killing power than the 180 grain 10mm Auto load. As a big game hunting cartridge the .41 Magnum is clearly superior.

In fact, although it is not commonly realized, the 10mm Auto is actually more comparable in power to the .357 Magnum. Federal, for example, offers a .357 Premium Handgun Hunting load that launches a 180 grain bullet at a MV of 1250 fps and ME of 625 ft. lbs. from a 4" revolver barrel. This is more powerful than the best 180 grain 10mm Auto load, and most .357 Magnum hunting revolvers have barrels at least 6" in length, which will further increase the .357's edge.

Factory loaded ammunition for both the .41 Magnum and 10mm Auto is widely distributed but by no means common or inexpensive. The same could be said for handguns chambered for the two cartridges. In availability of both ammunition and guns there is little to choose between the .41 Magnum and 10mm Auto.

Both cartridges are a straight forward proposition for the reloader. Common bullet weights for the 10mm Auto run from about 135 grains to 200 grains. For the .41 Magnum jacketed bullets span the range from about 170 to 220 grains, and cast lead bullets run up to about 300 grains. The reloader can essentially duplicate the factory loaded velocities in either caliber.

Revolver cartridges, however, are always more flexible in terms of reloads than cartridges designed for semi-auto pistols. Revolvers can tolerate a much greater variety of bullet weights and loads than auto pistols because they do not depend on gas pressure or recoil momentum for correct function. Maximum pressure big game hunting loads with heavy bullets as well as light recoil practice loads can be developed for the .41 Magnum that are simply not possible in 10mm Auto. And, of course, revolvers don't eject their brass onto the ground.

To summarize, there are probably better choices for personal protection than either the .41 Magnum or 10mm Auto, although both will serve well in experienced hands. Today, the primary appeal of both is to the recreational shooter and hunter. For the latter, the .41 Magnum is by far the more effective cartridge.

Ammunition and guns for both calibers are reasonably available, but not thick on the ground. In this area there is little to choose between the two. Both cartridges are easy to reload, but the .41 Magnum is the more versatile cartridge for the reloader.

If a shooter insists on a semi-automatic pistol for field use, the 10mm Auto is one of the very few calibers worth considering. As a big game hunting cartridge it should be compared to the .357 Magnum, however, not the .41 Magnum. For those not wedded to the semi-automatic pistol, the .41 Magnum is the superior cartridge in almost every way.

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Copyright 2003, 2013 by Chuck Hawks. All rights reserved.