A rocket motor comprising: a case ; a nozzle system including first and second nozzles disposed in the case , the first nozzle at least partially disposed in the second nozzle ; and a fragmentation system (134; 234), at least a portion of which is disposed between the first and second nozzles ; wherein the first nozzle includes: a convergent section that narrows to a throat section that expands to a divergent section , a forward leg forming the convergent section , a rear leg forming the divergent section , and an intermediate leg between the forward leg and the rear leg , wherein the rear leg has a rear lip that is spaced from the case such that there is a rear gap (G2) between the rear lip and the case , the forward leg and the rear leg at least partially defining a flow passage through the first nozzle ; characterised in that : the intermediate leg has a convex conical geometry ; the forward leg has a forward lip that is spaced from the case such that there is a forward gap (G1) between the forward lip and the case , and the first nozzle is exclusively secured by the intermediate leg to at least one of the case or the second nozzle . a case ; a nozzle system including first and second nozzles disposed in the case , the first nozzle at least partially disposed in the second nozzle ; and a fragmentation system (134; 234), at least a portion of which is disposed between the first and second nozzles ; wherein the first nozzle includes: a convergent section that narrows to a throat section that expands to a divergent section , a forward leg forming the convergent section , a rear leg forming the divergent section , and an intermediate leg between the forward leg and the rear leg , wherein the rear leg has a rear lip that is spaced from the case such that there is a rear gap (G2) between the rear lip and the case , the forward leg and the rear leg at least partially defining a flow passage through the first nozzle ; characterised in that : the intermediate leg has a convex conical geometry ; the forward leg has a forward lip that is spaced from the case such that there is a forward gap (G1) between the forward lip and the case , and the first nozzle is exclusively secured by the intermediate leg to at least one of the case or the second nozzle . a convergent section that narrows to a throat section that expands to a divergent section , a forward leg forming the convergent section , a rear leg forming the divergent section , and an intermediate leg between the forward leg and the rear leg , wherein the rear leg has a rear lip that is spaced from the case such that there is a rear gap (G2) between the rear lip and the case , the forward leg and the rear leg at least partially defining a flow passage through the first nozzle ; characterised in that : the intermediate leg has a convex conical geometry ; the forward leg has a forward lip that is spaced from the case such that there is a forward gap (G1) between the forward lip and the case , and the first nozzle is exclusively secured by the intermediate leg to at least one of the case or the second nozzle . the intermediate leg has a convex conical geometry ; the forward leg has a forward lip that is spaced from the case such that there is a forward gap (G1) between the forward lip and the case , and the first nozzle is exclusively secured by the intermediate leg to at least one of the case or the second nozzle . <EOS>