What is better 9 mm or 40 caliber guns?

Answer 1

A .40 caibler Smith & Wesson cartridge is also called a 10mm. So it has a larger diameter bullet and more casing to hold more powder. Therefore it is a more powerful bullt than a 9mm Lugar Parabellum cartridge. The .40 S&W is 10mm in diameter, however, it is not normally referred to as 10mm, at least not in the U.S. The cartridge officially named 10mm was a different cartridge and cannot be fired from a .40 caliber handgun because it's too long to fit into the magazine or to feed into the barrel. The .40's case is 22 mm long and the 10mm is 25mm long. And whether a .40 caliber is more powerful than a 9mm is conjecture; it depends on whose statistics you choose to believe. In both calibers, as well as most any caliber, different cartridges have different specifications; different types of powder, different amounts of powder, lighter or heavier bullets, etc, all which can affect performance of the projectile, so to say that .40 is more power than 9mm is only correct when comparing some loads, but generally, .40 is considered more powerful that 9mm.