Help cant unlock ram-7

[deybit]

Hi, I recently started playing warzone, and I am having trouble unlocking the ram-7. For many shots to the head that with assault rifles, he does not count them, he always sets the counter to zero, so I can never unlock the weapon, I have 100 levels and I still cannot unlock this weapon. My battle net id is deybit # 2898 so you can check it
Please, can you help me?