I think buff is the way to go, not to tear down Shoulder charge to garbage - and sorry, I thought you were referring to hunter grenades. Definitely needing a fix though, sunsinger isn't useless, but it's very inconsitent now. In the current state solar grenades definitely should be able to stack on damage - if I have 5 in a pile and you stand in the middle, usually you only receive damage from one grenade.