Railguns are electrically powered electromagnetic projectile launchers. They can be extremely powerful. The main applications are military related, but railgun technology is being explored as a possible way to launch spacecraft. Reddit user zebralemur built what he claims is the largest portable railgun made by anyone other than a government.
Here is the creator showing off his homemade railgun.
The first launch was a success, though the connections were not secure enough to withstand the force.
These are the aluminum projectiles that the gun shoots.
During the second launch, the projectiles snagged and were partially vaporized. The result was spectacular.
The creator spent two years acquiring the 56 capacitors required to build the gun. The total cost was $2,600USD.
Here are the 56 capacitors that were used with the gun.
The next launch was aimed at ten fine ceramic China plates.
This is a closer look at the gun itself.
The last launch was aimed at this piggy bank.
Just in case it is not already clear, you should not try this at home.