Either platform can be larger than the other. The 45 has the larger projectile.
Caliber is defined as the diameter in fractions of an inch, so .40 caliber is smaller in diameter than .45 caliber. Caliber can also be defined in the metric system, measured in milimeters. The .40 caliber cartridge is equivalent to 10mm in diameter. As noted, the size of a handgun can vary widely within one caliber, so it is perfectly reasonable to have a smaller handgun crafted in a larger caliber.
45 has the larger projectile. Size of the handgun will vary.
Yes, a 45 caliber bullet is bigger than a 40 caliber bullet. A .45 is0.45 inches wide in diameter and a .40 is 0.4 inches in diameter.
A 40mm handgun would fire a bullet the size of a golf ball. No such critter. There IS a .40 caliber handgun (about 10mm). There are dozens of larger caliber handguns than .40 caliber. They include the .41, .44. .45, .455. .460, .475, .500- and several others.
Probably. It would likely refer to a handgun that fires a .45 caliber ACP, or .45 GAP or an older .45 caliber revolver round.
200
In most circumstances, no. The bullet is too large to chamber in the handgun.
A .45 caliber Colt revolver- a handgun.
Best to ask a gunsmith for help
Which .45 handgun are you referring to? The .45 Colt revolver (Peacemaker) goes back to about 1873. The traditional "45 Auto" was adopted by the US Military in 1911, but there were other, earlier .45 caliber automatics. And of course, .45 caliber black powder ball and cap pistols, ball and cap revolvers, etc are MUCH earlier than the Peacemaker. So... which handgun?
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.
If your question is can citizens of the US own a .45 cal handgun, the answer is yes. MOST of the US does not require a permit to own a firearm, and even the areas that DO require permits do not ban the .45. In some countries private citizens may not own a handgun in a military caliber, but the US does not follow that practice.
No. The AK-47 fires the 7.62x39mm round, which is of the .30 caliber, smaller than the .45 caliber.