Disclosed is a firing device for shock tube. Shock tube is a non-electric explosive initiator, well known to those of ordinary skill in the art. The firing device is configured to provide a redundant dual-ignition capability for connected shock tube. In this way, a second attempt to initiate the shock tube can be made immediately following a failed first attempt. To provide this functionality, the firing device includes a primer tray that can be preloaded with two primers. Using an operably connected selector, the primer tray can be rotated between use positions that individually locate each primer for detonation.