Here is an incredible list of top five coils guns, which I think are simple in making, but have good output. 1. ACG 85P 2 Stage Configurable Semi-Automatic Pistol: it is first of its kind portable semi-automatic coilgun pistol and can fire 5 shots per second at 2 joules. 2. Electromagnetic Pistol: CS-P01A: The gun has a capability to convert an energy of just 4.0J to a speed of 25m/s projectile fire. 3. EM-15 coil gun: This is a 12 VDC battery powered rifle that can fire .30caliber metallic projectile at adjustable velocities. 4. 18 Shot Repeat Coilgun: The gun uses a sophisticated mechanism to fire the projectile into the best position. 5. The Mk II Coil Rifle: This gun has a short charging tie of just 10 seconds and a firing energy of about 5 joules.