second coil means for electromagnetically sensing relative proximity and up and down displacement of said projectile in terms of {HEAD ~ currents} induced by the mechanical motion of {TAIL ~ the said projectile} 
second coil means for electromagnetically sensing relative proximity and up and down displacement of said projectile in terms of { HEAD ~ currents } induced by the mechanical motion of { TAIL ~ the said projectile }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL