No. The AK-47 fires the 7.62x39mm round, which is of the .30 caliber, smaller than the .45 caliber.
This is the approximate size of a .45 caliber round, the conversion being .443 inches.
Probably. It would likely refer to a handgun that fires a .45 caliber ACP, or .45 GAP or an older .45 caliber revolver round.
Assuming the question is in regard to firearms and ammunition, you can read the "caliber" of a round as a decimal how wide the bullet is in inches. So a .40 caliber round is .4 inches wide, or about 10.16 millimeters wide. A .45 caliber round would be .45", so a little bit fatter than the .40 caliber round. The caliber doesn't tell the whole story of a round though, it doesn't say how long the bullet is, how heavy, how big the casing behind the round is, how much kinetic energy is hits with, etc. The .40 S&W round has an average of 425 ft/lbs of energy right at the muzzle, while the .45 ACP, a "bigger" round, has about 400 ft/lbs.
.40 Smith & Wesson is a 10x22mm cartridge, whereas the .45 ACP would measure 11.65x23 in metric measurements. The .45 is a larger round, and also a much slower round.
A 410 shotgun is basically a 41 caliber smoothbore. A 45 caliber round may fit in the chamber, but the bullet is too big. Don't do it.
2500 fps give or take
my opinion is the 45 ACP round has more knock down powder then the 40 caliber
The Colt M1911 and the colt M1911A has only 1 caliber .45 or 45/100 of an inch. This round is also known as the colt .45 A.C.P. (all Colt pistols) It is a short round which differs from the .45 long round.
A ".45 caliber" can be a gun that uses .45 caliber ammunition or it can be a round of that ammunition. There are several specific calibers of small arms ammunition that are all generally called ".45 caliber." They have bullets that are roughly .454 of an inch or 454/1000 fractionally. A famous .45 caliber is the .45 Long Colt, invented in the 1870s and still popular today. It is used in revolvers. Another caliber that is the same diameter but a lot shorter in length is the .45 ACP or .45 automatic Colt pistol. It was made for use in the U.S. military's Model 1911 handgun, and it is still a popular caliber today in that gun and in other handguns. There are some rifles and carbines that use .45 caliber ammo, too.
45
Caliber (or calibre) is a measurement of the inside diameter of the barrel, and is also used to refer to the particular cartridge fired by a given gun. A .45 caliber gun fires a bullet that is ROUGHLY .45 inches in diameter. A 9mm uses a bullet that is ABOUT 9mm in diameter.