9mm Ammunition: History and Variations

9mm pistol handgun ammunition
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9mm ammunition is now the most popular round in the world for handguns. Prior due about 1900 .45 ammunition was the standard, but at roughly the turn of the century, manufacturers began to put emphasis on smaller caliber .30 rounds due to their greater velocity and improved accuracy.  The .30 rounds proved lacking in stopping power, however, and in 1902, German manufacturers introduced the 9 mm (also known as the 9 x 19, or 9 mm Parabellum).

Used initially in the Luger and other European weapons, the Parabellum had a slightly tapered cartridge jacket that was designed for easier loading and jam-free use.

The terms "Luger" and "Parabellum" refer to this same round--a 9mm round with a slightly tapered jacket. The term "Nato" refers to exactly the same type of rounds. No entry on this venerable old cartridge would be complete without some mention of the oft-repeated claim that "parabellum" means "prepare for war." 

It was not until after World War II that 9mm rounds overcame the .38 among police departments in the United States, however, when they began to experiment with 9mm in order to improve accuracy. Today, the 9mm is second only to the .40 Smith & Wesson round in U.S. police departments. The 9mm is preferred because it is cheaper, kicks less and is thus more accurate, and because more rounds can be held in the magazine.

Casual users may see all 9mm as the same, but be aware that there are many different types available.

These include the 9mm Action Express, 9mm Bayard Long, 9mm Browning Long, 9mm Centerfire (which is actually a shotgun shell, if you can believe it), 9mm Makarov, 9mm Ultra, 9mm Winchester Magnum, and 9mm Kurz (380 ACP) just to name a few.

Some military-style ammunition features hotter gunpowder loads with harder primers, which are ideal for submachine guns, but which should not be used in the average 9mm handgun.

 

Users have long recognized performance differences between Luger/Parabellum rounds and other 9mm auto rounds. On-line forums are full of stories about jamming with Luger/Parabellum rounds, and a 2014 analysis by Shooting Times magazine traced the problem to the slightly tapered jackets on Luger/Parabellum rounds. Newer straight-jacketed rounds, known as "Automatic" rounds, do not exhibit the same jamming problems.