Simple automatic weapon system using a magnetic base and magnetic projectiles. Small wooden sticks separate the magnets and a long wooden stick works as a trigger. Range is about 7 meters.
Step 1: What You Need and Measurements
What you need to replicate this experiment:
1. Rod magnets
2. Ring magnet
3. Non-ferrous barrel. (plastic, wood, glass...) copper nor aluminum isn't ideal. Eddy currents will slow the projectile magnet down. The inner diameter should be very close to the diameter of the rod magnet. I used a plastic pen.
4. Small sticks for separating the rod magnets
5. Longer stick to push the magnets through
The projectile rod magnet: Ø 4 mm, height 25 mm, N42, nickel-plated, strength approx. 640 g pull force.
The base ring magnet: Ø 60 mm x 15 mm, Ø 15 mm hole in neodymium / 8 mm hole in the metal casing, grade N35, 100 kg pull force. I used two of the together.
Step 2: Function
When the rod magnet is being pushed into the hole with same
polarities N-S < N-S. The rod magnet would turn 180 degrees but since it doesn't have the room to turn it catapults from the ring magnet's hole.
The small wooden sticks separate the magnets in the barrel. This enables to shoot the projectiles individually or as a burst controlled by the trigger stick.