9mm Major  

I am a big fan of the 9mm Major cartrige.  I'm not sure where I first ran across it. The concept is simple: take the 9mm Luger (Parabellum) and load it to higher pressures, originally so as to have similar recoil to .45acp for pistol competition.
Here is what Wikipedia has to say about it:

9mm Major, also known as 9 Major, ammunition is loaded much hotter than typical 9mm rounds, exceeding 1,550 ft/s (470 m/s) to achieve a power factor of 165. This classification benefits competition shooters maximum magazine scoring. However, it is not readily available and dangerous to use in pistols not designed for such high pressure. Many handgun manufacturers that use plastic internal parts will caution against using
+P and +P+ ammunition and 9mm Major loads, which generate even higher chamber pressures. In tactical situations, velocity improves vest penetration, If not designed properly, it will affect hollow-point projectiles' behavior. It is important that the bullet be designed to expand and stop within the threat to maximize energy transfer. Col Fackler of the Army Ballistic Wound Lab studied this phenomenon extensively. The bullet needs to create a permanent wound channel, not a temporary one like most hollow-points and ball ammo. Proper cartridge design is crucial for optimal performance.

The popularity of 9mm Major has risen due to the lower cost of 9x19 Parabellum cases compared to .38 Super cases, as well as the versatility of using guns designed for the shorter 9mm Luger cartridge. Competitive shooters in the Open Division often handload their ammunition to customize their loads for optimal performance. However, some ammunition manufacturers like Atlanta Arms, JJR Ammo, ORM Tech and Universal Ammo produce 9mm Major rounds with competitors in mind.

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