Sorry I didn't even see these messages until now on my profile. Anyways as far as Civil War goes, yeah there are a couple glitched achievements (or ones that don't unlock when they should), mainly the pistol one for me. As far as a sign in trick, the only thing I did was go to my hard drive and delete the saved game. Then go back into the game like you're starting brand new and play the first level of one of the 2 campaigns (don't remember which one, long time ago). Whichever one you start with a pistol. Only use the pistol to get kills if you can. You should unlock it then after a level or two. If not delete the save again. Only do this after you've completed the game if you plan on doing that or else it will erase your level progress. Good luck.
Hey, I'm wondering if you could please help me. I was reading your posts in the Civil War thread from a while ago, and you mentioned that when you were trying to get the last few achievements (namely the Pistoleer one), you erased your game data with "the sign in trick" and it reset your stats for the game. How is this done? I want to give it a shot.