Starting some more comprehensive testing, small player primaries do 1% of normal vs. Big Damage, small player secondaries 5%, as expected (starting at full HP!). If given explosion radii however (no shockwaves), the explosion damage seems to be 0.01% for primaries and 0.25% for secondaries (so the crazy player nerf divides damage by 100 or 20 for the impact, then 100 or 20
again for the explosion? TBH sounds like a "bug" in Retail, if it is in Retail). Shockwaves always do full damage vs. Big Damage, aside from distance attenuation.
I should attach a flag to my phone that says "supercap" to make it indestructible.
It also turns out that shockwaves from small weapons do full damage to supercaps, so EMP missiles will slowly but surely destroy your phone, making it call random people in the meantime.