A process is disclosed for assembling a loading tube for a perforating gun for use in a perforating system. At a first location, e.g., a shop, which is not the location at which perforating operations will be conducted, the loading tube is completely assembled. The completely assembled loading tubing is then transported to a second location where perforating operations are to be conducted. In one embodiment, an RF-safe initiator, wiring, a detonating cord and a plurality of shaped charges are installed into the loading tube at a first location. The RF-safe initiators may comprise an exploding foil initiator or an exploding bridge wire. A process for assembling a loading tube for a single-shot perforating gun is also disclosed.