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