Primaris don't need Heavy Flamers.

They have PYREBLASTERS(TM)(R). They are SUPERIOR to pathetic firstborn manlet weapons. Those who cross the rubicon look down on the pathetic short dwarves that are their predecessors with autistic scorn. BURN IN THE FLAMES OF THE PYREBLASTER. The time of firstborn is over. The time of the PRIMARIS MARINE is now!

PRIMARIS ARE KING.