"Caliber" is a term used to describe the internal diameter or bore of a firearm's barrel or the diameter of the projectile (bullet) it fires. It is typically expressed in either inches or millimeters, depending on the measurement system used.
In the United States, caliber is often expressed in inches. For example, a firearm with a bore diameter of 0.30 inches would be referred to as having a ".30 caliber" bore. Similarly, a firearm with a bore diameter of 0.45 inches would be described as having a ".45 caliber" bore.
In many other countries that use the metric system, caliber is expressed in millimeters. For instance, a firearm with a bore diameter of 9 millimeters is referred to as having a "9mm caliber" bore.
Caliber is an essential specification for firearms because it determines the size of ammunition that can be used with a particular gun. The ammunition for a firearm must match its caliber to function safely and accurately. Different firearms are designed to use specific calibers of ammunition, and it's crucial for firearm owners to select and use the correct ammunition for their guns.
A furlong is a unit of length that is used primarily in horse racing and some other sports, as well as in some older systems of measurement. In modern terms, one furlong is equal to 1/8th of a mile. This is equivalent to 660 feet or 220 yards.
The term "furlong" has historical roots and was originally used in medieval England as a way to measure distances for plowing fields. Over time, it became associated with horse racing and is still used today to describe the length of a horse racing track. In horse racing, races are often measured in furlongs, and the distance of a race may be referred to as "6 furlongs" or "10 furlongs," for example.
While the furlong is not commonly used in everyday measurements, it is still relevant in certain specialized contexts, particularly in horse racing and related sports.