This thread could get ugly... Americans and their guns and their right to bare arms!
When was the last time the King or England walked into your house???
There's no need for this thread to get ugly if only facts are shared. After Australia's gun ban, violent crimes have drastically risen. I understand that even "ceremonial swords" have been banned as well...
The right to self-defense, like in Great Britain and Canada, is not recognized in Australia. A fundamental freedom was extinguished from you and sadly you don't acknowledge or apparently understand that travesty. A country who has fought for the freedoms of others is now stripped of the one freedom that guarantees all others.
To my fellow countrymen, don't be fooled into thinking that it can't happen here as well.
Mikey speaks the truth, a 9mm will not drop a man when hit center mass. It will most likely take several shots. A .40 can, but a .45 WILL lay someone down. There is a reason that bullet is big, bulky and ugly.
Also, there are very few agencies anymore that carry 9mm, most are .40 and some departments are reissuing the 1911 .45.
Ugghh... The old 9mm vs .45 debate. It's probably the most talked about topic in handgun discussions. So much misinformation being provided that it's almost impossible to separate the facts from the emotions. My advice is whenever you hear/read the words, "Best" or "man-stopper" or "one shot, one kill" type of answers, run away... Not directing this at you, slynger.
No pistol cartridge is really the wondrous "man-stopper" that we think and want it to be. Basically, unless you hit something truly biologically vital and/or structural, the "bad-guy" may keep on coming. Don't rule out the psychological aspect as well. Getting shot is an emotional trauma as well.
Bottom line is both will do the job if you hit where you aim. Pick the one you shoot best and train properly with it. Caliber is only one small part of picking the "best" defensive round.
Pray that you are never placed in a situation where you are called to use it. But if so, I sincerely hope that you have sufficient training in defending yourself and your loved ones.