The CAR-15 (Colt Automatic Rifle-15 Military Weapons System) is a family of AR-15 and M16-based firearms developed by Colt in the late 1960s and early 1970s, designed to be compact, lightweight versions of the larger AR-15 rifles.
The CAR-15 is a weapon featured in Battlefield Vietnam, issued to MACV and ARVN Assault kits. It has a high rate of fire, moderate recoil, high damage, high accuracy and a magazine capacity of 30 rounds. Its high rate of fire and capacity can make it be effectively used as a submachine gun, and compared to the M16A1, it's a better choice for any combat.
There is also a CAR-15/XM148, exclusively issued to the MACV Assault. It is basically the CAR-15, but it replaces its ability to aim and increase accuracy with the quick ability to use an under-barrel grenade launcher. It is not necessary to switch to the grenade launcher, hence making aiming impossible, by using the secondary fire button. It's a generally welcomed addition to close-quarter situations as the XM148 has a very limited range and an extremely noticeable arc in its trajectory. The inclusion of the XM148 in the Assault kit gets rid of the hand grenades.