General achievements question

So for those of you that have played the game extensively I have a question I need to clarify, please.

Its regarding the unlocking of Achievements,do you have to be im Ranked server/match for any achievements to unlock, or can some of them be done in private matches and is this for both versions?

Hey Jeff, I've got the 360 version, and I would like to join you if you're on the same version - we can work towards these together!

Yea I have both and planned on doing both, so you're more than welcome to join, but I was told that achievements only unlock in Ranked and someone else said they did everything in private? So I was just trying to get some clarification on this. Now that I'm doing a little research, I think the guy who told me private really meant public... But the same question stands, do achievements unlock in public? I don't want to waste a bunch of time if my progress is not going to mean anything in public matches.

I never did anything in other then ranked matches. That said you can change your region to like Japan at the title screen (by pressing X) where there is no one playing on the servers. Match up with your group and unlock what you need. Maps will be random.