Bat­tle­field 3 received a big patch a month ago which rebal­anced a tons of stuff.  Good to know that most changes are pos­i­tive, but I then had to read­just play style to the post-patch game­play.  Many acces­sories on guns act dif­fer­ently post-patch.  I had to dig around the wall-of-text patch note on my own, and then con­duct much test­ing that I WISH THIS ARTICLE WAS THERE BEFORE I HAD TO DO THAT.

http://blogs.battlefield.com/2012/04/inside-dice-perfect-setup/

READ IT. IT WILL HELP YOU! (Espe­cially if you want to be a lazy ass like me :)