Initiator assembly that is resistant to shock

An initiator assembly that includes a header body, a frame member, a plurality of terminals, an initiator chip, a plurality of contacts, and a support member. The frame member is coupled to the header body and defines an interior aperture. The terminals are received through the header body and the frame member. The initiator chip is received in the frame member and has a plurality of lands, a conductive bridge and a flyer that is disposed over the conductive bridge. Each of the contacts is soldered to an associated one of the terminals and an associated one of the lands. The support member is formed of plastic and encapsulates the frame member, the plurality of contacts, and a portion of the initiator chip. The support member forms a barrel aperture over the flyer. The input charge is formed of a secondary explosive and is disposed in-line with the barrel aperture.