[3.2] 100% Fire Pen Blast Rain Deadeye - Rains of Blastamere - Updated League Gear Options

I don’t understand how anyone sustains blast rain on bosses. I have like 12-15 ex of gear on this build and I can’t cast a 6l blast rain more than like twice. I have the claw nodes and a mana leech node in ranger tree, I just don’t get it.