INVESTIGATION OF 3-INCH/70 CARTRIDGES FROM AMMUNITION LOT PV-4-C-57

Abstract : The premature ignition of a 3-in/70 cartridge aboard the USS WILLIS A. LEE (DL-4) resulted in a serious casualty. Various tests with cartridges and cartridge components from the same ammunition lot, PV-4-C-57, failed to reproduce a similar preignition. It was concluded that: the cartridges from ammunition lot PV-4-C-57 appear to be serviceable; the premature ignition, upon ramming, of a 3-in/70 cartridge probably would not be caused by solid propellant grain slivers or black powder grains becoming lodged between the cartridge case and projectile; the wad for a full case assembly is not adequate for all 3-in/70 full service charge assemblies; the proposed bullet pull-out load requirements are unrealistic for the Mk 34 Mod 3 projectile; and that electromagnetic radiation was not the cause of the casualty. It was recommended that two Pc. No. 26 (wads) be used in a full case assembly, a wad of 4-inch diameter be adopted and used together with two distance pieces whenever Pc. No. 26 is inadequate.