I was thinking about making a GPS tracker shooter. You could use it to shoot a GPS tracker onto the back of, say, a Truck in front of you that was driving really bad. I got cut off by a semi one time that didn't have a "How well am I driving" sign on the back. I think they were running drugs.
Anyways, I'm not really familiar with all the different KNEX guns, as to which is most reliable and accurate and easy to build, etc. Can you recommend one that might be able to shoot a small GPS tracker from one car to another about 30 feet away?