You know, I really don't wanna be an asshole, but questions like these are what GOOGLE is for. For instance, type in "c7 rifle statistics" and you'll get info on everything you ever wanted to know about the damn thing. Example:
http://www.eme421.com/c8carbine.html
STATISTICS
Length: 100 cm (C7) // 84 cm (butt extended) // 76 cm (butt retracted) (C8)
Weight (with loaded 30 rounds): 3,8 kg (c7) // 3,2 kg (C8)
Quantity: 79, 935 (C7) // 2,365 (800 for the Navy) (C8)
Muzzle Velocity: 920 m/s (C7) // 865 m/s (C8)
Ammunition: 5.56 x 45 mm
Magazine Capacity: 30 rounds
Type of Fire: Single Shot and Automatic
Range - Maximum: 2350 m
Range - Effective: 300 m
Year Procured - 1986
Manufacturer - Diemaco (Kitchener - Ontario)
Now if you want clarification on what those numbers actually mean, fine, ask. But do a little bit of research first. Since you seem to be interested in what exactly the numbers in a caliber measurement mean, you could try typing "how is caliber measured" into google, and you'd receive the following response:
http://en.wikipedia.org/wiki/Caliber
In firearms, the caliber is the diameter of the inside of the barrel. In a rifled barrel the distance is measured between the lands. The measurement is in inches and the caliber (abbreviated to cal) is quoted as a fraction (hundredths or thousandths) of an inch, so a 0.22 inch smallbore rifle is .22 cal.
Outside Great Britain and the U.S., the caliber of a weapon is commonly expressed in millimeters (mm). It is technically incorrect to say 9 mm cal. If referring to the inside diameter of a barrel, you should say 'the caliber is 9 mm'.
The caliber of a weapon is often informally used to describe certain common weapons. A .45 cal pistol is called a '45', a 9 mm semi-automatic pistol is called a '9 mil', a .380 caliber is called a '380', etc. This gives rise to the impression that "cal" is a unit of measurement, equal to 1/100 or 1/1000 of an inch, whereas it is just an unfortunate figure of speech.
For historical reasons, the name of a cartridge is not always the actual caliber. As one example, the common .38 Special revolver actually fires a bullet 0.357 inches in diameter.
Note that caliber alone is not a good indicator of the deadliness of a cartridge. Bullet weight and shape, powder capacity of the cartridge, and length of the barrel are some of the many variables which also have an effect.
Small arms range in bore size from approximately .177 cal up to .50 cal. Arms used to hunt big game may be as large as .700 caliber. In the middle of the 19th century, muskets and muzzle-loading rifles were .58 cal or larger.
Caliber as measurement of length
Relationship of caliber in bore and length of gun
The length of the barrel (especially for larger guns) is often quoted in calibers. The effective length of the barrel (from breech to muzzle) is divided by the barrel diameter to give a value. As an example, the main guns of the Iowa class battleships can be referred to as 16"/50 caliber. They are 16 inches in diameter and the barrel is 800 inches long (16 * 50 = 800).
Alternative measurements of bore
Measurement of the bore of large weapons can be, and often was, expressed in pounds. A sphere of lead of the same diameter as the bore would have a certain weight. Lead is a useful material because it is malleable though unsuited for large projectiles because of its density.
This leads to certain guns being referred to as 6-pounder, 25-pounder, et cetera.