Currently the Smith and Wesson 500 S&W Magnum. However the 460 S&W although smaller and lighter is much faster with much more range and accuracy especially with a good scope(deer at 300 yards!).
No
Unknown
A VERY good handgun- for most puposes. Durable, reliable, accurate, and powerful.
Probably, almost certainly, the .600 Nitro Express is the overall most power handgun bullet. Let me alter this answer by saying the .600 Nitro Express is a rifle round that one company made a pistol for. The most powerful handgun cartridge is the 500 S&W Magnum.
Not even close. There are several more powerful handgun cartridges, not counting the single shot pistols that use rifle cartridges. While Dirty Harry may have proclaimed it to be "The most powerful handgun in the world"- it is not.
There are many handgun rounds that exceed the 44 mag. 454, 460, 500 to name a few.
Fairly certain it is the Thompson Contender .600 Nitro Express for production firearms.
Can't be answered withou knowing if you are referring to a rimfire or centerfire 22
No, not by a longshot (no pun intended). Almost all "major" caliber handguns are more powerful than the 9mm.
Rifle, shotgun, or handgun? The 10 gauge shotgun at close range would be very high on the list, as would some of the buffalo rifle cartridges, such as the 45-110. The .45 Colt revolver was possibly the most powerful handgun of the day.
The .500 S&W magnum is the most powerful handgun round commercially available.
Dirty Harry used a 44 Magnum in his words "The most powerful handgun in the world." Specifically, it was a Smith and Wesson Model 29 in a .44 magnum. In addition, it is not the most powerful handgun in the world (not even at the time of filming.)