Private > 500 MP
Specialist > 1250 MP
Corporal > 2500 MP
Sergeant > 5000 MP
Officer > 10000 MP
Lieutenant > 16000 MP
Captain > 25000 MP
Major > 35000 MP
Colonel > 50000 MP
General
I can consider creating more ranks, but abbreviations (such as Gen, Capt) will have to stay small.
If ever, I can leave the abbreviated tags the same. Like 5 star and 4 star share the same abbreviation (Gen).