True to the Battlefield spirit, the latest Battlefield 3 patch fixed a lot of thing, but it also included a few bugs on its own. And you have most likely come across that bug while playing the game: the M26 MASS attachment for the assault class is way overpowered due to a glitch. When the M26 is equipped with DART ammunition and the underslung grenade launcher, each dart deals full damage of the main rifle. Which means instant-kills across most ranges.
But DICE is aware of the issue, and according to Gustav Halling (via Twitter), the M26 glitch will be fixed in an upcoming patch. However, he didn’t give a timeline as to when we can expect the patch. Needless to say, the patch can’t come soon enough, as the M26 glitch is getting out of hand already. Given how long it took for previous patches to be released, it looks like we’ll have to live with this for a little while.