Post originally by Derek Murphy at 2003-09-01 18:49:59
Converted from Phorums BB System

Little history:

Luger developed the 9mm Para in 1902 because the German military wanted more stopping power than could be had from Luger's 7.65mm round. The 9 is a 7.65 case with an open mouth to take the larger bullet. Originally, the round was a conical, flat-tipped round, but the tendency to jam led to the development of round-nosed bullets which have persisted to this day. John Browning's .45 ACP round was more popular in North America, and the 9mm didn't catch on here until S&W created the Model 39 in response to the U.S. military's search for a new pistol in 1953. When the army canceled the trials, S&W released the pistol to the civilian market.

The primary advantage of the 9mm over the .45 ACP (from a military standpoint) is magazine capacity. The secondary advantage is cost (not trivial when you're purchasing millions of rounds). The U.S. military was also influenced by the fact that the round was used by all of the allied forces in NATO.

BTW, the advantage of 5.56mm over 7.62mm is also mag capacity -- 7.62mm is by far a superior round over long distance, but experience shows that most combat scenarios take place at relatively short range (certainly the case in Vietnam). 5.56mm also has much less of a shoot-through problem in urban environments, with less of a chance for "collateral damage," aka civilian casualties.

Anyway, the 9x19 cartridge has been in use for more than 100 years now, which makes it hard to accept that it is a "fad." Most shooters in the U.S. are not going to see the main advantage of the 9mm because of the absurd U.S. laws prohibiting more than 10 rounds in a magazine, which is about the max you can get into most .45s regardless.

SOCCOM uses the .45 precisely because it is much easier to push subsonic. The round also definitely has more stopping power, which is important if you're fighting drugged up Taliban (or drugged up Moro rebels in the Phillipines). In a one-to-one shoot-out, having a .45 is a better option. On the other hand, in an extended firefight you have more tactical flexibility with a larger amount of ammunition. Less skilled shooters are also better with more, lower powered shots than fewer, higher powered shots, as they're more likely to miss the target. 9mm is also easier for a less skilled firer to shoot.

Neither 9mm nor .45 ACP are ideal for every circumstance, hence the move to .40 S&W in an attempt to overcome the weaknesses of both cartridges.

As I said, I shoot 9mm because they cost less, and because most burglars are not going to be drugged to the gills or wearing vests. As for reliability, the only problems I've had shooting my Glock have had to do with getting the lubrication right. Glock's are notoriously sensitive to over-lubrication, so that has more to do with the pistol than the ammunition.

Some of the details in this post come from <I>Military Small Arms of the 20th Century</I> by Ian Hogg and John Weeks, or from <I>The Complete Encyclopedia of Pistols and Revolvers</I> by A.E. Hartink.