Its around 1000 kills to get to 50.
The slowest part is 40 to 50 where there isn't any attachments.
Took around 750 kills with the mini scout (high damage assists help).
And in Casual Breakthrough that is probably 4000 kills...
That's on you for playing casual imo.
it makes so much sense to make xp different in game modes, jesus **bleep**
It's complete nonsense I get punished for playing differently. I also don't want to kill 1000 human players with a pistol, it's complete nonsense.
You don't want to play the game to earn attachments? You're crazy bro. Then what's the point of playing?
