A perforating gun system may include a first gun carrier and a second gun carrier connected to the first gun carrier. A perforating gun assembly may be provided in each gun carrier, the perforating gun assembly including a top connector, a plurality of charge holders, and at least one bottom connector. Upon rotation of the top connector, the one or more charge holders of the first gun carrier may be aligned in a zero-degree phasing with the plurality of charge holders in the second gun carrier, and the position of the top connector may be locked along the length of the second gun carrier.