I may be missing some lore here, but the JSA have a station on dawn, which according to the JSA Starter pack, is on top of nessium and tessium veins, so why don't we have t2 or k1 weapons?
Having access to tesseum isn't the same as having so readily access that it can be wasted on T2 or AP bullets. I don't think K1 is tesseum. I presume that all they get from that vein is going into O-Yoroi and Karakuri maintenance. P.s. or sold to Pan-O to pay off some pretty hefty security debts :p
Tessium are used in high technology, if I remember correctly it's used in cubes for example. So for everyone other than Ariadna it's way way too valuable to be thrown away as ammo.
just because they have a vein doesn't mean its available in large enough quantities or have the technology/ refining output to use it to forge swords and ammo
T2 ammo manufacturing is incredibly inefficient, especially for factions with the technological base to produce multi weapons. To the point where Irmandinhos sell them on the black market by weight and most buyers simply refine them back into Teseum ingots. K1 is super bleeding edge, potentially voodootech, and similarly expensive, so is probably either just beyond JSA's capabilities. Or the facilities that could produce it are busy making those fancy monofilament katanas for the Oniwaban.
There are 3 possible explanations. 1. Yu jing is making sure you cant mine/refine/ship it, like they did in the paradiso global campaign. 2. All advanced materials are going to the construcion of spaceships to bridge and secure the routes between their outposts. 3. Pay debts to everyone who backed their secession.
K1 ammo isn't Teseum. It's combine alien tech. Human factions getting access to certain combine tech (plasma and k1) is why the exrah concordat are NOT a playable faction anymore. (Exrah decided to sell weapons to both the combine AND humans (under the table) and got caught. The EI wiped out the entire corporate hive structure of the concordat as punishment for the crime. The next exrah hive in line don't have a battlefield presence.). While YJ and PanO also have colonies with teseum deposits, none are as rich and accessible as Ariadna's ones on Dawn. PanO also doesn't like to share.