There has been a revolver made in caliber .600 Nitro Express. This was an elephant rifle cartridge. As a firearm, it is a curiosity, and not a practical shooting firearm. There are also unconfirmed reports of a Maadi bolt action pistol in caliber .50 BMG.
You will haver to define if "biggest" means caliber or overall size.
It depends on whether you mean legally, or what is the biggest handgun available, and whether you mean handgun size, or caliber size. The largest commonly available caliber is .45 ACP, however, .50 AE is also fairly common. That said though, there is also a handgun available in .600 NE. Most states don't have restrictions on caliber, however, some may.
No, you cannot safely shoot a .45 caliber bullet from a .40 caliber handgun. The .40 caliber handgun is designed specifically for .40 S&W ammunition, which has a different casing size and bullet diameter compared to the .45 caliber. Attempting to use .45 caliber ammunition in a .40 caliber firearm could lead to dangerous malfunctions or serious injury. Always use the correct ammunition specified for your handgun.
Assuming you mean a bullet fired from a .22 caliber handgun, the answer is, yes, it can, but it depends on several variables.
Yes, colt makes a few different versions of the 22 caliber handgun such as the Woodsman, and Challenger.
It should be marked as to caliber on the barrel.
Its the size of the bullet that the gun is made for. its the caliber that a handgun uses
There are many handgun rounds that exceed the 44 mag. 454, 460, 500 to name a few.
No.
Probably. It would likely refer to a handgun that fires a .45 caliber ACP, or .45 GAP or an older .45 caliber revolver round.
.32 caliber. In a semi auto handgun, probably .32 ACP
45 has the larger projectile. Size of the handgun will vary.