The invention is based on the discovery that when at least a part of the initial burning surface of an epoxy cured carboxy terminated rubber type composite propellant is coated with a propellant antioxidant material, an increase in resistance to oxidative hardening and an increase in strain capability is imparted to said surface. The invention provides (1) such a composite propellant coated at an initial burning surface with a propellant antioxidant in an amount sufficient to impart those unexpected improvements, (2) method involving coating the burning surface with the requisite amount of the propellant antioxidant material, and (3) a propellant rocket motor containing the above said propellant. When only a portion of the surface is subject to high strain, e.g. in slot areas, it is sufficient that only that portion of the burning surface be coated.