All of it is lethal. There is no one "magic" bullet.
Any metallic bullet fired from a gun can be lethal. Pistol ammo is not designed for different degrees of lethality, but is designed for effectiveness in stopping and attacker. That is likely to be a jacketed hollowpoint cartridge.
Absolutely not.
No. Only shoot the caliber printed on the barrel.
Yes
It depends on what you are using it for and which one groups best.
They come in different sizes. 50, 100 and 500 are the most common.
.44-40
Different calibers. The Model 19 is in caliber 9x19mm, the Model 23 is a .40 caliber. The 19 holds more ammo in the standard magazine. External dimensions and weight are the same.
The .40 caliber bullet is a little larger in diameter and is a little heavier (under most circumstances). The .40 will usually have more powder, velocity, and muzzle energy. Also, the .40 is designed for use in a semi-automatic and the .38 is a revolver cartridge.
The most common hand-gun caliber used to be 9mm Luger. Recently I bought a pistol and took a self-defense course. Now it seems the most popular caliber is the.40 Caliber Smith and Wesson.********There are popular, and there are most common. The most common gun caliber is .22 rimfire, in terms of the total number sold.
No
the 40 cal is a little bigger then the 357