this is the original
(here is the link for the original:https://www.instructables.com/id/semi-automatic-knex-pistol/
Credits To BedBugg
Step 1: The Stock
here we make the stock
picture 1=make this twice
picture 2=make this
picture 4=snap them on it like this
Step 2: Semi or Full Auto?
in step 3 part e of the original you make the trigger you see 2 of those green things who not are connected if you remove the lower one then when you hold the trigger you got a full auto gun.
Step 3: Grenade Launcher
in step 1 of this instructable you saw a green connector on the stock if you make the splodie grenade launcher from bedbugg you can connect it with this.