FESTERS PLACE

imagine i get 5 headshots with a sniper in a single round.

Now imagine that, a month after those 5 headshots, a sniper pack comes out with an achievement where i have to hit 5 headshots in a single round.

Do i have to hit 5 headshots again, or will i automatically earn the achievement?


thanks for the help

For one thing valve won't overlap specific achievements, so more than likely they would have an achievement for 7 headshots in a round or something like that.
With the medic achievements it took into account how much healing you had done in total, but not, say, how many scouts you had killed with your needle gun. So you started one achievement fresh and had already done some of the work for another.
The pyro seemed to be a blank slate, everything had to be done after the point of the update.

So the safest bet is just that, only what you accomplish after the update will count towards achievements.
Unless its like "play 10 hours as sniper", then i would expect then to count the past.
You never know.