Tendency to self-ignition of special gun propellants during dynamic grain compression experiments.

Dynamic compression of granular propellant samples as a standard test procedure for qualification of a gun propellant always encloses the risk of self- ignition. In spite of respecting the safety limit to compress a propellant sample only to a maximum loading density of not more than 85 % of the density of the propellant material, self-ignition especially of D-propellant samples (containing Dinitrotoluene) has been observed. Dynamic compression tests with other types of gun propellants under the same test conditions did not show any chemical reaction. Systematic experiments with special test methods described in this presentation manifested that the high values of dynamic toughness of the D-propellant during dynamic compression and an especially dense granular bed can lead up to the threshold of self- ignition. Generally, the procedure described here can be used to estimate the tendency to selfignition during dynamic compression of any type of gun propellant.