I doubt the technology Norh Korea has developed is capable of long range accuracy. With the rest of their country so far behind the modern world I cannot see how they are technically advanced in this area.
Without the support and technology from China .
China does not want an aggressive North Korea that will have to be subdued in the future.
The US ralized after the cold war that the Soviets were more bark than bite. Hopefully North Korea is just banging its own drum to secure the new leaders posistion. Shalom