I want to make a coilgun with 2 or 4 stages; however, I don't have much experience with capacitors, magnetic fields, etc.. I am not really making it now, but its more of preparing the steps so when I do start, I will be able to complete it and be aware of problems that may occur. 1) when the coil is fed with electricity, what is stopping it from shooting right back at you? 2) how much voltage should the coils be using (aka what type of capacitor should I use) 3) I have heard that capacitors will sometimes have left over charge in them, how would I "dump" the excess. 4) Using multiple stages, should all the coils be turned on at once or in succession 5) should the wire coiling the tube be uninsulated? Here is a diagram of my current understanding of a coilgun. Let me know if it is not correct. Power Supply (battery) --> switch --> capacitor -->wire that wraps around the pipe, creating a magnetic field --> magnetic field pulls projectile into the tube and launches it.