Continuous Solvent-free Extrusion of Propellant for 35 mm Calibre Ammunition

Abstract

In the frame of the evaluation of new 35 mm calibre projectiles, a propellant was manufactured by using a solvent-free continuous twin screw extrusion process. This was developed for the manufacturing of JA-2 equivalent gun propellant for large calibre ammunition [1]. In order to obtain the required combustion rate, a significantly smaller web size, and hence smaller grain size, of the 19-perf propellant grain is required than for the JA-2 equivalent propellant. For this purpose a new die technology was developed and applied. The firing test results showed excellent reproducibility, which is attributed to the homogeneity of the propellant composition and smooth and reproducible flame spreading over the propellant bed. These results demonstrate the applicability of a solvent-free and continuous manufacturing process for propellants used in medium calibre ammunition.