Enter the following stats for your character, and you will be given stats about how you can increase your ranking. Enter the data in the same format that it is displayed in the game.

If you can't figure out how to enter data:
For Ammo Used, entering either 250K or 250000 is fine (but do not use commas).
For Time, enter as dd:hh:mm if you have played at least 1 day (use colons to separate the fields).
If you haven't played at least 1 day, then it'll be displayed as hh:mm.ss (use a period to separate the minutes and seconds).
This is important, since 2:00:00 is 2 days, while 2:00.00 is 2 hours.

Thanks to AgentSam for finding out the complete list of milestones you need to level up. You can see them here.