I did the 500 void in a two hour stint. I did it with defender Titan. Sticky grenade (void) fusion rifle and (void) LMG. Both were rares. Voidwalker warlocks also have an easier time with this bounty. You need to predict the heavy weapon spawns. Play cautious and keep at mid range at all times. Keep distance from the shotgunners. The trick with the fusion rifle is to charge it up preemptively. Watch the radar. And keep a wall at your back. Play control missions. More people and the enemy is more distracted. Note: The quality of your weapons makes no difference.