It has no AoE damage and is only affected by primary damage effects. Burst radius modifiers change its projectile size
I don't get it. Burst ammo should have no effect on the size of the AoE burst radius at all, as it is a percentile increase of zero, which yields zero.
Does that, however, mean that addin incendiary rounds to the flamethrower increases the fire chance from 0.22 to 0.66?
That is, from 0.22 (0.22 from direct hit) to 0.66 (0.22 direct hit + 0.2 incendiary hit + 0.2 incendiary aoe hit).