Enjoy Double Weapon XP all weekend long.
Starting on Friday, April 19 (10am/PST) and going through Monday, April 22 (10am/PST) you will earn Double Weapon XP on all weapons. Double Weapon XP allows you to level up and unlock Attachments at twice the usual rate.
Is it all game types?
I just got done with a couple of TDM's and they didn't have double XP - although the splash screen was up indicating so.