It raises the chance of heavy ammo. The CHANCE. It's never definite that you will get lots of ammo drops, there's just a higher CHANCE that you will. Just like the most recent cryptarch update, which increased the CHANCE to get legendaries in the postmaster packages. You still get blues in the package very often, because it was only the chance, of getting legendaries, that was increased. I run the Ruin Wings and, yeah, there are plenty of times when heavy drops seem to dry up, but in general I am getting a lot more heavy drops, overall, than when I don't use them, or use a different class. I did VoG for the first time since getting the upgrade this week, and i spent probably more than half of the raid using truth, so in my experience the ruin wings work fine and don't need any fixing.