A high explosive firing mechanism, comprising: a housing comprising, a firing pin tube having a first surface and a second surface opposite the first surface and a primer inlet extending from the second surface; a firing pin disposed within the firing pin tube, the firing pin having a first end face and a second end face and comprising a nub that protrudes from the second end face , wherein, in a first position before firing the high explosive firing mechanism, there is a distance d between the second face and the second surface , the housing further comprising an input tube ; a transition tube providing fluid communication between the input tube and the firing pin tube; and a high energy transfer line coupled to the housing and configured to transfer expanding gases to the first end face of the firing pin within the firing pin tube, wherein the high explosive firing mechanism forms a portion of an aircraft egress system, characterized in that in the first position the distance d is such that the nub partially extends into the primer inlet . a housing comprising, a firing pin tube having a first surface and a second surface opposite the first surface and a primer inlet extending from the second surface; a firing pin disposed within the firing pin tube, the firing pin having a first end face and a second end face and comprising a nub that protrudes from the second end face , wherein, in a first position before firing the high explosive firing mechanism, there is a distance d between the second face and the second surface , the housing further comprising an input tube ; a transition tube providing fluid communication between the input tube and the firing pin tube; and a high energy transfer line coupled to the housing and configured to transfer expanding gases to the first end face of the firing pin within the firing pin tube, wherein the high explosive firing mechanism forms a portion of an aircraft egress system, characterized in that in the first position the distance d is such that the nub partially extends into the primer inlet . a firing pin tube having a first surface and a second surface opposite the first surface and a primer inlet extending from the second surface; a firing pin disposed within the firing pin tube, the firing pin having a first end face and a second end face and comprising a nub that protrudes from the second end face , wherein, in a first position before firing the high explosive firing mechanism, there is a distance d between the second face and the second surface , the housing further comprising an input tube ; a transition tube providing fluid communication between the input tube and the firing pin tube; and a high energy transfer line coupled to the housing and configured to transfer expanding gases to the first end face of the firing pin within the firing pin tube, wherein the high explosive firing mechanism forms a portion of an aircraft egress system, characterized in that in the first position the distance d is such that the nub partially extends into the primer inlet . an input tube ; a transition tube providing fluid communication between the input tube and the firing pin tube; and a high energy transfer line coupled to the housing and configured to transfer expanding gases to the first end face of the firing pin within the firing pin tube, wherein the high explosive firing mechanism forms a portion of an aircraft egress system, characterized in that in the first position the distance d is such that the nub partially extends into the primer inlet . <EOS>