Most of the guns that people make out of Legos or Knex are pistols. Small, easy to build, low maintenance. Those are all fine qualities. But if you want a powerful, destructive Lego gun that will blow all others out of the water, check this video out. It features step-by-step instructions for building a minigun out of Legos that will hold and shoot 120 rubber bands at a time! The second video is a firing demonstration. Those Legos never knew what hit them!
From the creator:
READ IF CONFUSED
When you make the barrel on one side of it you will have seven holes I say to at least leave 5 what I mean is when you put the supports for the barrel in you put it six spaces into the barrel so if 0 marked holes and X marked holes that the support structure is in it would look like 00000XX for a 8 barreled and on the other side it would look like 0XX