Some information about mod items.

1. How can I get Mk.II?
It has no spawns so you have craft it from Mk.I and some upgraded parts.

2. How can I get ammo?
You can craft ammo with Charger supply item or find it. You also can craft makeshift power charges but they have big damage penalty.

3. Why energized power charge is so expensive to craft?
It is basically a raiding magazine. Explosion on impact will have pretty same stats as one used in rocket launcher. It can be used only by Mk.II tho ;)

4. Triple Upgrade
You can craft it from three upgrades but be carefull it has overall smaller stats.