Depends on how many kills you get but it would take more then one game to gain 70k kills.
The way it always worked for me and i have tested this with dummy accounts a few times, 200kills for 1 down, so looking at your stats
742downs X 200 kills per down = 148k kills tottal
it is approximate figure, all stats count so you could get top around 120k if your other stats are good.
