Woooo..... It is another model, not really based on anything but when I put the vector mag in it kinda reminded me of a G18.
EDIT: MOAR PICTUERS!!!!!!
Edit No. 2: will be posted although no as seen in the latest pic, that one is mine
Last edit: Finally posted because I was bored: https://www.instructables.com/id/Knex-Sidearm-Model-1/