I just fail to see how Gauss tech was considered a deadend, yet railgun tech wasn't. The two are extremely similar in nature. The only real difference is made obvious by the names: railguns use rails, and coilguns use coils. The coils allow a Gauss gun to become far smaller than a railgun, which requires a pretty long barrel. Railguns are usually ship-to-ship weapons, while Gauss guns are typically for close-quarters combat between people.

I assume our ship will be mounted with railguns from the start, since modern cannons as we know them will be totally ineffective in a vacuum.