Thank you for your kind reply. This is exactly what i am doing right now. And it works. Just solved it with some help from discord ue channel, before i saw your post above. 
i was almost doing the samt thing before i changed everything client side, becouse i was trying to figure out what is going on. The thing i did before is, that i started the server logic on the weapon. I still “used” the weapon localy on my pawn, and in the weapon i told the authority to run on server trace and call the interface on whatever we hit. I do wonder though, now that everythign is running server side, i noticed that i cant see my linetrace debug on clients anymore, is there a easy way around that? as use function is called server side from pawn now, everything on the “weapon is server side” thus, remote will never execute?