The AK 12 Kalashnikov Rifle is a Two Round Burst Assault Rifle. It's similar to the Famas in many respects, only the base damage is higher, and the rate of fire is also higher.
The FAMAS and AK 12 have similar damage models, with the AK 12 having the upper hand in raw damage, without accounting for headshots and criticals. Unfortunately, the AK 12 has a bad accuracy, lower than the Famas. This means that it is more effective at close range, also doing well at medium range.
There are several good qualities about this weapon. First, since it fires in two round bursts and the damage is high, per-shot recoil increase is largely negated and ammunition is conserved. Second, its close range capabilites make it more suited for agressive combat than the FAMAS.