I see Neun's post but the mats I know don't seem to be on that map so I'll add to it.
In Upper Bog there are great ammo materials. I'm not sure, but beckers bark might be found year round on the resin and wood spot between FFF and fencoomb. However, my only experience has been digging exhaustive amounts of excellent beckers in winter. It pops frequently and all over that area.
There is choice gulatch oil too in Bog which does good damage. If you specifically want koorin, I frequent a place in Nexus for that. While usually Nexus is a pain, the koorin is the easiest mat to get there, with the benefit of possibly yielding excellent and supreme. Just take the Elusive Forest Karavan TP and run to the Nexus portal, and the koorin is at the top of the hill when you come out. It's on the edge of torbak and gibbai aggro range.... but typically not dangerous. Well, and there's Wyac, but that goes for Bog too.
Hope that helps.
As far as ranged in general:
The hit rate stanza seems counter productive to helping ranged. The general consensus isn't that ranged isn't severely lacking in damage, but rather ammo is such a hassle to deal with. Why have a stanza that makes you burn up ammo FASTER? It would be so much more beneficial to have a stanza that DECREASED hit rate but with a gain of accuracy and damage. Make every shot count more. Maybe it could be something called "Vital Shot" that does double damage at half hit rate, or triple/quadruple damage when combined with an "aim" stanza and successful. Just my thoughts.
Edit: That would really only make sense for pistols/rifles and the bows. Not going to be sniping with an AoE gun, now are we? But launchers and autos woudl have their own stanza, as it sohuld be. The should get something unique for the same reason you can't use bleed on a mace
As for what it could be.... maybe a DoT? "Napalm bomb"? Takes twice as long to load the shot, but causes extra damage over time after the inital hit.