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

Both have the same issue of excessive barrel wear. Main difference is rail guns use no explosives at all. It’s all kinetic energy. It’s insane how much of a punch they pack. My limited understanding is that’s why we have not put any in service. The go through barrels too quickly