There are 5 assault rifles in Call of Duty Black Ops 4 to consider to find out which one is the best. With its low recoil the ICR-7 is a strong early unlock that can be used to hold down a position. The Rampart 17 is the highest damage assault rifle and is strong at medium range, especially when you are behind some cover.
The KN-57 is a good weapon that has great versatility in how it can be used due to its controllable recoil and good mobility.
The Vapr-XKG is a late unlock with extremely low recoil and the possibility of attaching a suppressor. The Maddox RFB is the last assault rifle you unlock and has a high fire rate and a good sized ammo supply.
However, the Maddox RFB is difficult to use because of its recoil. After you get the first two enemies you are often left without ammo to take on the next enemy, despite the large ammo supply.
The Rampart 17 is good at medium range, but its slow fire rate means that it has to be played in a very defensive way. The ICR-7 similarly is also good at holding down a position, but it is not easy to attack an enemy position.
The KN-57 is a strong weapon since it can be used to defend a position and also go on the attack and capture an objective. It is a close second to the Vapr-XKG that, with its low recoil and great attachments options, is a great tool in most firefights. With the level 2 stock enemies will struggle to hit you and with the suppressor you can concentrate on one enemy at a time without alerting nearby enemies. Therefore, the Vapr-XKG is the best assault rifle in Call of Duty Black Ops 4.