In most games assault rifles are a bit better at range (generally higher muzzle velocities and it takes longer before the bullets hit their minimum damage range), but they're both very competent weapon classes and their differences are usually not noticable.
Carbines have better hipfire, but worse velocity and 2 tiers of damage dropoff (They'll take 2 more bullets to kill at range than they do up close). Assault rifles have excellent velocity and only one tier of damage dropoff. Assault rifles are generally considered better than carbines.
In the real world, a carbine is a shorter, lighter version of a weapon, generally designed for use by drop troops (where a full sized rifle often injures a soldier on an iffy landing) or for indoor work (where the shorter weapon is easier to bring to bear in close quarters). In game, assault rifles are a bit more accurate at range (better recoil characteristics) than their carbine counterparts, and only appear in Medic hands.
in ps2 carbines have worse damage fall off then ARs, and are generally slightly less accurate as well.
The Carbine is an Assault Rifle with noticeably worse performance at range but with better hip-fire. Carbines are used by Light Assaults and Engineers while Assault Rifles are unique to Medics.
From what I can tell on TR.. Assault Rifles for Medic have a silly RoF with low/medium damage. It's seem to be for defence, where as carbines are for offence. Carbines have a semi-silly RoF with slighty more power, so there are on par with SMGs but perform better at range. VS have simlar weapons to TR when it comes to Carbines. NC have some High RoF and slow RoF Carbines, some hit fast, some hit hard.. some prefer power over control.
