A 4-million-amp current runs through oppositely charged rails on either side of the barrel. A shell, which weighs about 35 pounds, is placed onto a conductive seating.
When positioned between the two rails, the seating completes the circuit. At that point, a burst of power, called a Lorentz force, hurls the projectile out of the open end of the barrel.
The projectile goes from zero to 5,000 miles per hour in 1/100 of a second. It can strike with 32 megajoules of energy, roughly equal to the force of a locomotive smashing into a wall.