You need at least One Target to get a Rank

E-1 Private 0 Kills
E-2 Private First Class 10 Kills
E-3 Lance Corporal 30 Kills
E-4 Corporal 60 Kills
E-5 Sergeant 100 Kills
E-6 Staff Sergeant 150 Kills
E-7 Gunnery Sergeant 200 Kills
E-8 Master Sergeant 300 Kills
E-8 First Sergeant 400 Kills
E-9 Master Gunnery Sergeant 500 Kills
E-9 Sergeant Major 600 Kills
E-9 Sergeant Major of the Marine Corps 800 Kills

W a r r a n t  O f f i c e r s

W-1 Warrant Officer 1000 Kills
W-2 Chief Warrant Officer 2 1200 Kills
W-3 Chief Warrant Officer 3 1400 Kills
W-4 Chief Warrant Officer 4 1600 Kills
W-5 Chief Warrant Officer 5 1800 Kills

O f f i c e r s

O-1 Second Lieutenant 2000 Kills
O-2 First Lieutenant 3000 Kills
O-3 Captain 4000 Kills
O-4 Major 5000 Kills
O-5 Lieutenant Colonel 6500 Kills
O-6 Colonel 8000 Kills
O-7 Brigadier General 9500 Kills
O-8 Major General 12000 Kills
O-9 Lieutenant General 14000 Kills
O-10 General 16000 Kills
O-11 General of USMC 50000 Kills
O-12 Field Marshall 70000 Kills
O-13 Field Marshall NOTAP 100000 Kills