Material farming

[NI.TO]

I need help with material farming for weapons, also some of the weapons I cannot upgrade even if I have materials for it, don’t understand why?
I’m on 2nd series of missions or difficulty 2

[Nox667]

upgrading weapons requires both the materials and having reached their rank in the progression.
a rank 3 weapon will only be craftable once you reach rank 3 missions in the story for example