Cocked&Locked said:

You stand alone in the world in that opinion. The only defining article of an "assault rifle" is the mid-power cartridge. Carbine is a term refering only to length. To be technical about it, you could have a carbine configured assault rifle. Such as the CAR. I would be curious to find one creditable reference to "assault rifle" that didn't begin with the cartridge. An AK is much bulkier to handle than a M-16 weapon, weight/girth have nothing to do with it.
Oh...I don't know about that...for a while I worked with these weapons and worked with NATO soldiers from around the world. The common definition we had of a battle rifle had to to with the length, girth and purpose of the weapon.
It seems to me if we go by calibre than the CAR, FN MiniMI machine gun, and M16 could all be classified at the same thing. So I am not misunderstood, rifles are typically classified by length and action, not calibre.
An SLR / Battle rifle is typically longer with less ammo, heavier, and the emphasis is on aimed shots, marksmanship, longer ranges, and pentration. Many, like the early FNs were only select fire after special modification requiring a tool (typically a bayonet).
Assault rifles are shorter, typically select fire, often with more ammo and smaller calibres. The emphasis shifts to bursts, firepower, and rounds down. These weapons are often used to supplement the killing power of MGs in the field.
Carbines are the shortest of all rifles, many of which shoot small rifle or pistol calibre. A CAR would be an example of this. Typically they are best applied to short range, high firepower applications such as con space, fibua, spec apps, or overland foot recce.
There are bolt, lever, slide action, and semi auto rifles that fire pistol calibres. There are machine guns that fire deer hunting (7.62 / .308) calibres and machine guns that fire varminting (5.56 / .223) calibres. There are pistols that fire rifle calibres. There are rifles that fire grenades, and there are shotguns that fire slugs.
These categories are not rigid, there is a lot of blending. For example, a M14 with a barrel chop and sage stock has really become a carbine. As a gas gun, it's more like a SLR in its internals, but externally, it meets all the criteria of a carbine. It calibre of course remains the same. As such, firearms are not defined by calibre, but by structure, function, and purpose.