9 mm versus .357 Sig

by
posted on November 13, 2013
wiley-clapp.jpg (1)

A reader was interested in a 9 mm/.357 Sig comparison after I discussed the 9 mm cartridge versus the newer .40 S&W. In the 9-to-40 comparison, we have a smaller, lighter bullet versus a slower, heavier one. The bigger, heavier bullets of the .40 S&W have already established a good reputation for fight-stopping performance. But a typical pistol will hold a few less of them than a comparable-sized 9 mm auto. I think that adequate capacity of more effective 40s renders the 9 mm’s advantage in both capacity and velocity a very moot point. Still, the 9 mm has some advantages in easier shooting and training, as well as lower cost and longer gun life.

To compare the 9 mm to the .357 Sig is an entirely different ball game. First used by the German Navy in 1904, the 9 mm Luger (or Parabellum, etc.) has a long service history and is probably the most widely used pistol cartridge in the world. The little round came into its own in the 70s when modern JHP ammo was developed. Capable of good velocities, particularly with lighter bullets, the 9 mm cartridge is made for dozens of pistol designs. Although made with typical 115-grain bullets for many years, the most commonly used 9 mm Luger bullet today weighs 124 grains. Heavier 147-grain JHPs are becoming more popular.

The .357 Sig is a recent cartridge that has one characteristic exactly like the 9 mm Luger-it uses the same 124- and 147-grain bullets. Despite the name, the actual bullet diameter is 9 mm (.355 inches). It differs in that it is uses a bottlenecked case developed from the .40 S&W. Among other advantages, this means the gun’s breech dimensions and magazines are the same as the .40’s. Building a gun is usually no more complicated than installing a .357 Sig barrel in a .40 S&W pistol. With greater case capacity of modern powders, the .357 Sig is a very hot number. I have heard reports of accelerated gun wear.

There is an enormous array of 124-grain ammo in 9 mm, including some +P and +P+ that is extra hot. The average velocity for all loads at this weight is about 1,100 fps. Now look at the average velocity of an admittedly smaller assortment of .357 Sig ammo using bullets of the same weight. It is approximately 1,350 fps. In other words the typical 125-grain JHP load travels 250 fps faster in a 357 Sig than in a 9 mm Luger. In the 147-grain bullets, the 9 mm drives bullets to about 1,000 fps, while the .357 Sig does about 1,225, some 125 fps faster. There is a clear speed advantage to the Sig, not at all surprising in view of the larger case capacity.

When you crunch the numbers through the formula that calculates kinetic energy, the 9 mm gets approximately 336 ft.-lbs. for 125s and 326 for 147-grain slugs. The .357 Sig is way ahead at 506 ft.-lbs. for 125 grainers and 490 for the 147-grain bullets. Inescapably, the .357 Sig is a much more powerful cartridge.

That does not make it a better cartridge. It recoils strongly, has lesser capacity in same-size guns and may be hard on guns. Using it skillfully takes practice and familiarity. These are pretty subjective matters, which prompts the observation that if you can handle the .357 Sig, it is an automatic pistol cartridge that wildly out-performs the 9 mm Luger and even equals the legendary .357 Mag.-when the latter is using 125-grain bullets.

Latest

LLE Leadweb
LLE Leadweb

The L42A1: A Sniper Rifle To Remember

For most of the 20th century, Lee-Enfield rifles were the backbone of the British army. The last British service Lee was the L42A1 sniping rifle. Built on the World War II No.4(T), the reliable and accurate L42A1 was retired in the early 1990s.

The Armed Citizen® July 30, 2021

Read today's "The Armed Citizen" entry for real stories of law-abiding citizens, past and present, who used their firearms to save lives.

NRA Gun of the Week: Uberti USA 1873 Single-Action Cattleman New Model

On this week’s “Gun of the Week” video preview, American Rifleman staff take to the range for a closer look at Uberti USA’s special edition "Teddy" revolver, a replica of Colt's New Model 1873 SAA. 

Kentucky Rifle Raffle to Celebrate the 25th Anniversary of Contemporary Longrifle Association

In celebration of the 25th Anniversary of the Contemporary Longrifle Association, Judson Brenman and sons have made a masterpiece contemporary Kentucky Longrifle for a raffle held by the organization for the occasion.

The ArmaLite Story

The history of ArmaLite is long and tortured, filled with marvelous innovation and crushingly bad timing. Yet, now it looks like its day has finally dawned.

The Immortal Winchester Model 94: From the 19th Into The 21st Century

Since its invention at the end of the 19th century, the Winchester Model 1894 lever-action rifle design has become an iconic American firearm that is still produced and celebrated to this day.

Interests



Subscribe to the NRA American Rifleman newsletter