The ammunition now has to be safe in each climate zone especially abroad when carrying out UN missions. For use in a combat aircraft for example the ammunition should have a high cook off stability in order not to undergo a self ignition reaction of the propellant while lying in the hot gun barrel. On the other hand there is still the demand on a high ballistic performance at a low barrel erosion. Accordingly, conventional single and multi base propellants border on their limits. A new type of propellant solves the problem. Based on RDX, a nitrocellulose binder and a three component energetic plasticizer, this gun propellant disposes of a high ignition temperature of about 210°C and a significantly improved chemical stability compared with conventional gun propellants. Beside a high force constant at a comparable low adiabatic flame temperature and a low molecular mass of the reaction gases, what in sum is of value in terms of barrel erosion, the novel gun propellant has a further outstanding property: The burning rate hardly depends on the propellant temperature which means that the temperature coefficient in Vieilles burning law is low. That is why we call that propellant a Low Temperature Coefficient (LTC) propellant. Because the burning rate does not depend much on the propellant temperature the maximum gas pressure in the gun does not as well. Therefore the maximum permissible gas pressure can be exploited to full advantage what can be used to increase the muzzle velocity. In the meantime the LTC gun propellant has been investigated successfully in the medium caliber range. The results of that propellant type will be given and be discussed.
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