What is CPTO?

What are the initials of the army ranks?

PVT - Private (E1) PV2 - Private (E2) PFC - Private First Class (E3) SPC - Specialist (E4) CPL - Corporal (E4) SGT - Sergeant (E5) SSG - Staff Sergeant (E6) SFC - Sergeant First Class (E7) MSG - Master Sergeant (E8) 1SG - First Sergeant (E8) SGM - Sergeant Major (E9) CSM - Command Sergeant Major (E9) SMA - Sergeant Major of the Army (E9) WO1 - Warrant Officer, Grade One WO2 - Warrant Officer, Grade Two WO3 - Warrant Officer, Grade Three WO4 - Warrant Officer, Grade Four WO5 - Warrant Officer, Grade Five 2LT - Second Lieutenant (01) 1LT - First Lieutenant (O2) CPT - Captain (O3) MAJ - Major (O4) LTC - Lieutenant Colonel (O5) COL - Colonel (O6) BG - Brigadier General (O7) MG - Major General (O8) LTG - Lieutenant General (O9) GEN - General (O10)