Yeah, you guys are taking a lot of damage.
Try to keep your Sin and PT tanks at 10m away from Bulo. This keeps the minecarts away from your melee dps and makes it harder for them to cleave each other.
Neither tank has any healing. Jugg's Enraged Defense and Sin's Overcharged Saber are powerful defensive cooldowns. Make sure they're using them. I'm fairly certain you don't have a PT tank (Close and Personal) but if you do, the Shoulder Cannon healing utility in Heroic can be picked up to help ease the burden on your healers.
Scatter Blaster hitting for 20k is normal when it's neither shielded nor defended. Your tanks should be using cooldowns for this. Taunting during Scatter Blaster keeps Bulo from switching to the other tank, so don't do that.
Whoever is running barrels needs to be ready to pick one up as soon as the adds spawn. A tank can aoe taunt the adds to keep them off healers if the barrel runner is a bit slow with the barrel.
Make sure your dps and healers are moving out of Mass Barrage and Volley. Try to kite Load Lifters away from the group if you notice it's on you. Don't plant Mass Barrage or Volley on or in the way of your team.
Pro tip: You can place 2 Mass Barrage circles in the same spot before you start to take damage from either one of them. As long as you move immediately after the second circle is planted, this should help increase your dps, and give everyone more safe space to move around in.