Does rapid shot just suck? Wtf is going on

I have crazy damage gear for my level (20) and ive been wanting to make rapid shot work. But it just doesn't. I dont understand why...

11-33 damage from crossbow

11-19 cold damage
1-14 lightning damage
10-27 physical damage
9-17 fire damage

Fresh clip (+52% damage)

This is fully specced into damage with not much defence (its hardcore so i need this to pay off). Yet i can pump several rounds worth of rapid shot into a rare mob. One rare snake in sekhema, at my level, took 5 clips, or 250 attacks.

This appears to be either bugged, or else im missing something, but i dont know what it would be. I cant think of any other reason for me to be doing negative damage with this amount of gear.

Even if rapid shot does 23% of the above damage, that would still be the equivalent of over 40 attacks to kill a rare snake. With a melee character it would take maybe 5 attacks with this damage.

crossbow skills suck overall. it needs balancing

A pack of 3 white crabs took 6 clips. This is definitely bugged, idk how people play crossbow. Its a crossbow not a fucking grenade launcher.