Could railguns create another Dreadnought moment?

Could a future warship make contemporary ships obsolete in the way HMS Dreadnought did?

Yes. The first ship with an operational railgun could create a comparable step change and provoke a new naval arms race.

Naval competition already contains a continuous effort to outbuild or outdesign rivals. A step change becomes a Dreadnought moment when one working system renders many existing comparisons obsolete. A practical railgun installation is one plausible modern example. The strategic shock would depend heavily on whether Japan, the United States, China or Britain reached operational service first.