The new Marine codex introduces a whole new weapon type to the game of Warhammer 40,000.
There’s new article up on Faeit 212 posted by Nafka:
Grav-Weaponry and Its Dramatic Effect on Our Game
http://natfka.blogspot.ca/2013/09/grav-weaponry-and-its-dramatic-effect.html#more
There are a few parts to the rules for these weapons which look like they need a bit of FAQ help, but one thing is for certain: They’re here to stay.