It is not very neat, but I didn't have much time as it was only meant to be an alternative way of building an airsoft gun using a new system (part of my GCSE project). My design fired 9mm steel ball bearings, which is fun, but can cause injury.
This does use voltages upto 400V, and comnpressed air, so be carefull, and never put anyone at risk from whatever you manage to create.
The railgun is a form of linear accelerator, using a electromagnetic force to propell an object. The way that these work is that a electrical current is conducted up one rail, across the projectile, and then back down the other rail (see picture). This is called the Lorenz force.
Please ask if you have any questions.
This is my first instrucatble, so please be nice...
Step 1: Parts
For the Compressed air system; (step 4)
Gas reservoir- I used 4 small one, but a large single would be perfect, or use a spring.
2 gas valves- 2 gives a faster rate of flow, but not necessary if using a spring.
Pneumatics pipes- reservoir to valve to barrel connections
Steel tube (barrel)- diameter must be similar but slightly larger than you projectile.
For electrical (the rail gun)
I used 10 400 volt 450uf aluminium electrolyte capacitors (step 2)
Solid aluminium bar (for rails)- 20cm x 3cm x 3cm (step 3)
Acrylic 20cm x 3cm x 0.2cm