As far as I can tell though they don't seem to have any proximity ability, as they can miss by a hair and carry on into the black.
They do have quite an impressive range on them though, especially if you launch them mid burn.
Changing one value in phase_charge.proj however provides a much more satisfatory performance:
"behaviorSpec":{"behavior":"PROXIMITY_FUSE",
"range":120,
Changing the proximity range from 75 to 120 seems to give them enough room for the ability to actually work as expected.
The fall off from never getting the core damage is more than offset by them actually hitting something.
It could do with the OP cost dropping a bit though.
Currently costs 10 OP for 30x500 or 15000 dmg.
Typhoon also costs 10 OP but has 5x4000 or 20000 dmg.
Prox. has 75% dmg capacity, so 7 or 8 OP?