of the bolt catcher frame an aperture 65 exists at the interior rim of the junction of the frame and the top to accommodate the upturned edge of the guide upon ejection of the separation bolt in operation the pyro squib 45 of the missile stage connection assembly is connected to an electrical signal output upon receipt of such a signal the pyro squib ignites the explosive charge 49 the explosion shatters the diaphragm 47 causing the expansion of gases through tube 39 into channel 35 drilled counter bore 37 allows the transfer of the gases and attendant pressure into the chamber 30 which exists surrounding ejector piston 23 and the interfaces 67 and 68 within the separation nut assembly 13 the increased pressure in the chamber bounded by the ejector piston held in threaded engagement to bolt retainer 13 causes the downward movement of nut inner housing 22 relative to separation nut body 33 due to the fact that their corresponding surfaces are smooth and unthreaded the interface between rectangular ring 21 and bolt retainer 19 is smooth a relative downward movement of ring 21 due to its threaded engagement with nut inner housing 22 relocates the ring to a more constricted geometry of the bolt retainer lessening the inward or retaining force on the lower portion of separation bolt 17 the release of the retaining force on bolt 17 coupled with the buildup of pressure in.