?...PS Railgun + Synth Exploit = 117% dmg (but you never have to resynth).
I don't know about any synth exploit - is that a real exploit? or one of those features that some players choose to call an exploit (like board-swapping)?
The bit about never having to resynth sounds exploity to me - the premium ammo synth is definitely supposed to consume resources every time, so only having to do it the once shifts supposedly consumable ammo into a permanent component of the weapon - It'd surprise me if that was intended.
If I were to imagine a legit route to premium plasma slug ammo, I'd say that since the 'ammo' is made directly from ship fuel, perhaps if you used the synth materials as an additive to convert your ship fuel to premium fuel, that could do it? The premium fuel could last the whole tank, or until you scooped or bought fuel, at which point it'd fill up on standard fuel and you could synth again with materials if you wanted.
An idea like that would have some snags -you'd have to deactivate your fuel scoop to avoid losing your premium fuel when moving systems, and habitual refuellers would have to think about whether they really needed to refuel at every stop.
Thanks for pointing out that PS only does a 10% penalty now - I guess I missed a patch note 'coz I feel sure it was a 20% penalty back when I last built some PS mod weapons, and I had it in my mind that this was still the case - so this makes my objection to PS modding only half as strong as it was!