FINAL REPORT: DEVELOPMENT OF A PAX-21 LOADING PROCESS FOR THE 60MM M720E1 HE MORTAR PROJECTILE

INTRODUCTION

The Program Manager for Mortars (PM Mortars) has initiated efforts to develop high explosive (HE) mortar cartridges having Insensitive Munition (IM) characteristics. PAX-21 is a new melt pour IM explosive recently developed through a joint effort between the US Army Armament Research, Development and Engineering Center (ARDEC) and Thiokol Propulsion to replace Composition B, the current HE fill for mortar cartridges. A process development program was conducted in Building 810, TACOM-ARDEC, Picatinny Arsenal, NJ to establish a melt pour process for loading 60mm M720E1 HE mortar projectiles with PAX-21. Experiments were conducted and an initial melt pour loading process developed to provide loaded projectiles for Type Classification (TC) testing, IM testing and process information to support future production development efforts. A total of 923 each 60mm mortar projectiles were loaded in a series of 20 experimental runs. The results from radiograph x-ray inspection of the 923 mortar projectiles demonstrated that acceptable explosive casts can be produced using the initial melt pour process parameters. It can be suggested that based on the results of this initial effort to load PAX-21 and with additional development, a high probability of an efficient, cost effective and safe production PAX-21 melt pour loading process can be achieved. The 60mm M720E1 is scheduled to go into full production in FY01. Plans to scale-up from the pilot plant facility will be presented, which will include prove-out of the melt pour and the controlled cooling processes.