I really like the weapon designs, all three variations. The materials are ok. They work in the presentation scene you created.
However, I’m not really digging the holes along the barrel over the grip.
They look kinda off, compared to the other modeling work you have done on the model. Maybe you should revisit these parts and try to figure out something else.
Looking forward to see what you will do with the textures. I think a weathered look on the metals would definitely benefit the overall appearance of the shaders.
Greetings from Hamburg,