is not simple; it can generate substantial transients which momentarily modify or reverse the classic conditions.  The NEWPORT NEWS out-of-bore prematures in 1971 (paragraph11) provide an example:  if analysis of them is correct, rough propellant performance initiated the BDF while the projectile was somewhere within the bore, and only the .01-second delay pellet in that fuze prevented these initiations from causing one or more high order in-bore projectile detonations.  Though the reduce-charge propellant anomalies associated with those events may have been corrected, other well-known factors encountered in service can also give the projectile a rough in-bore ride.  BDF manufacture/inspection derelictions comparable to those tabulated in reference (j) for the ADF could result in omission of the delay pellet.  Other errors could expose the fuze to more ready premature initiation.  In this connection we note that the re-certification program of reference (i) is not capable of providing added assurance concerning the BDF.  Hence the only BDF safeguard is positive inspection assurance prior to assembly into projectiles.

Other Potential Causes of Prematures

38.       Although it seems clear that this particular casualty resulted from an ADF premature, there is no justification for focusing corrective actions solely on that, to an extent that could cause us to lose sight of the need for substantial improvement with respect to all elements of ammunition safety in all fleet calibers.  Paragraph 7 depicts a glaring degradation of fleet ammunition safety since 1965.  The rate of in-bore projectile prematures per shot fired since that date has increased by a factor of more than 25 over the rate experienced throughout the preceding nineteen years.  That picture is substantiated for 8” ammunition by the appalling rate of deficiencies documented in reference (j).  The 23 shipboard in-bore prematures since 1965 have cost 24 lives, apart from their costs in combat readiness and material.

39.       Judging from the record noted in paragraph 9 and the findings recorded in reference (j), in addition to ADF malfunctions the other most probable causes of in-bore prematures appear to include BDF malfunction, defective projectile base sealing, and possibly gaps in the explosive filler (though this is uncertain for Explosives D).  The BDF situation is discussed in paragraph 37.  Our comments on these additional potential causes are as follows:

a.         Defective projectile base seals:  The record in reference (c) seems clear that these can cause prematures with either Explosive D or Composition A-3 projectile filler; and references (d) and (j) show that such defects continue to be found.  They are attributable not to contractors or DCAS, but to manufacturing and inspection deficiencies in our own naval ammunition facilities.  There are instructions intended to require back-up inspections of projectile base seals by fleet users, but these need clarification as previously noted, and in any case,