Level 42

Total Experience Required 352,649

Level 100 progress: 5.17%

This is roughly the same as:

Killing 588 people in Warzone, or...
Killing 600 people in Execution, or...
Killing 499 people in Wingman, or...
Scoring 125,947 points in Guardian, or...
Scoring 383,315 points in Annex, or...
Scoring 232,006 points in Submission.

Horde (TU4)

Completing 882 waves on Casual, or...
Completing 588 waves on Normal, or...
Completing 441 waves on Hardcore, or...
Completing 353 waves on Insane.

Or a combination of the above. Have fun!