Production of double-base propergol propellant blocks

The propellant blocks are produced from a base powder comprising nitrocellulose (of nitrogen content 11.5 to 13% by weight), a nitramine (octogen and/or hexogen) and a combustion catalyst system. The base powder is gelatinised in a mould at an elevated temperature by means of a nitric ester (e.g. nitroglycerine). The catalyst system comprises 2 to 5% by weight of an aromatic organic lead salt, 1 to 4% by weight of an organic copper salt or an aliphatic organic lead salt, and 0.1 to 2% by weight of acetylene black or benzene black, the percentages quoted for the catalyst system being based on the weights of the base powder. This enables a block to be obtained with high nitramine content (35 to 60% by weight), the resulting block having enhanced rate of combustion while still retaining uniformity of combustion.