When {HEAD ~ a flame} from an ignited flammable gas enters the conduit and ignites the explosive pack, the bullet is propelled into and frictionally engaging the inlet end of the conduit body such that an internal passageway in the inlet end is substantially blocked to prevent the further propagation of flame upstream into {TAIL ~ the conduit} 
When { HEAD ~ a flame } from an ignited flammable gas enters the conduit and ignites the explosive pack , the bullet is propelled into and frictionally engaging the inlet end of the conduit body such that an internal passageway in the inlet end is substantially blocked to prevent the further propagation of flame upstream into { TAIL ~ the conduit }
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL