Hi, i'm pretty new to the game. I like it, thank you.

I've reached level 13 now and did most of the challenges wich unlock new weapons and weapon modifications.
i've found you can click on the weapon to change it modifications, but I can't find my new weapons anywhere. I still have all standard weapons as I did from the beginning.
I should have a minigun, and some other weapons I really like to test out.
So where can I find them, if they are not on my regular weapon screen?
Greets