This is unquestionably the world's most popular pistol round. For this reason it has been the subject of a lot of experimentation, because 9mm ball, used by every army in the Western world, is a mediocre manstopper. Jacketed hollowpoints are a must if one wishes to rely on the 9mm as a defense round. Use ball ammo for practice only.
9mm ammunition is available in two pressure levels, standard and "+P." The latter should only be used in newer guns (made since 1985 or so) and is best used sparingly.
I will only deal with commercially available ammunition; there are specialized loads available only to law enforcement personnel. Civilians should not worry, as there are commercial loads as good or better than anything restricted to law enforcement usage.
I will now tell you the best 9mm Luger load for self-defense: it is the Cor-Bon 9mm 115 grain +P Jacketed Hollowpoint. This is the most powerful and street-proven manstopper available in this caliber. It is a high velocity (1350 fps) and high pressure round, more effective than any load restricted to law enforcement use, such as the Federal 9BPLE.
Unfortunately, it is also likely to jam many older guns. For this reason I add a table at the end of the 9mm section discussing round suitability for different guns. Modern hollowpoints may either (a) jam, or (b) be too powerful for some older guns. This load is suitable only for First Class pistols (see table).
The best standard pressure 9mm load is the Federal 115 grain JHP (9BP). Its effectiveness and accuracy make it the world standard. Buy several boxes. Other excellent standard pressure 9mm loads are the Winchester Silvertip 115 grain (X9MMSHP) and Federal 124 grain Hydra-shok (P9HS1).
For guns that may jam with the Cor-Bon or Federal 115 grain hollow-points, the Remington 115 grain +P JHP is a good choice (R9MM6). For older guns I would use the Remington standard pressure 115 grain JHP (R9MM1).
Bad 9mm Loads to avoid (and certainly NEVER carry). Numbers given:
Federal Hydra-Shok 9mm 147 grain JHP (P9HS2)
Winchester 147 grain 9mm Silvertip Subsonic JHP (X9MMST147)
Winchester 147 grain 9mm Super-X Subsonic (XSUB9MM)
Remington 147 grain 9mm JHP (R9MM8)
Remington 147 grain 9mm Golden Saber JHP (GS9MMC)
Table Of 9mm Pistols.
(Note: just because your pistol appears in Class 3 doesn't mean it is unreliable; it may indeed feed hollowpoints. However, you must fire at least 200 rounds of your chosen JHP carry load to determine if your pistol will feed them properly. I have placed pistols in each category according to reputation and experience. These are only meant as guidelines; your pistol may feed JHP rounds better - or worse - than this table indicates)
First Class pistols are ultra-reliable, high-quality new guns than can feed any hollowpoint and tolerate +P loads with no problems: SIG/Sauer P220 series. Czech CZ75 and CZ85. Walther P5, P5C, and P88. Heckler and Koch USP and P7 series. All Glocks. All Ruger 9mm pistols. Taurus PT-99, PT-92 and PT-92C. Steyr GB. Beretta 92 series. Browning BDM and Hi-Power (if it says "Portugal" on the slide). All Smith & Wessons with a four-digit model number (e.g. 5906, 3913, 6904, 5903) and the Smith & Wesson 900 series. Star M28, M30, M31, and all Firestars, Megastars, and Ultrastars.
Second Class pistols are high quality guns that may not feed all hollowpoints reliably. Remington 115 grain hollowpoints are recommended for these guns: Smith & Wessons with two or three digit model numbers (e.g. 659, 39-2, 469, 59, 39). Heckler and Koch VP70 and P9S. Beretta "Brigadier" M1951 and the Egyptian copy, the Interarms "Helwan." Colt Series 70 Government Model, Series 70 Commander. Astra A-70, A-75 and A-100. AMT "On Duty." Daewoo. Bersa Thunder 9. EAA Witness and all other CZ-75 copies (e.g. Tanfoglio, Tanarmi, Springfield Armory P9). Taurus PT-908. Walther P4. Star BK, BKM, Model B and Super. Browning Hi-Powers without the word "Portugal" on the slide. Llama Model 82. IMI "Jericho" and "Kareen."
Third Class pistols should generally be loaded with ball for best reliability - experiment with your gun extensively before carrying JHP: Walther P38, P4 or P1. Luger. Llama. Maverick. MKS Model JS. Intratec CAT-9, DC-9, KG-9, etc. SWD Cobray Model 11/9 and similar models. Scarab Scorpion. Kimel AP-9. Bryco Jennings Model 59. All KBI Hungarian pistols (e.g. GKK, PJ9C, P9HK and other FEG products). Norinco or Sportarms Chinese Tokarev pistols. Lahti. Radom. MAB P15 and Model 1950.