The nazi ww2 one is more similar to coil guns as the projectile is propelled by synchronized pulses. Rail gun is more similar to typical gun which has basically a single time pulse at the beginning (but magnetic field instead). There’s also light gas guns which have a gun power charge to move a plug that compressed a light gas like hydrogen Ina second chamber, which then bursts a membrane to then propel the projectile. Iirc sadam was doing light gas guns