Some research claims that overall damage and casualties in Seoul would be minimal, but those studies have relied on very conservative data, especially regarding the effective range of North Korean artillery systems. Many findings do not take into account newly deployed, modernized 122-mm multiple launch rocket systems with extended range, or the much more capable 300-mm multiple rocket launchers. If projectile flight distances reach proven ranges (or commonly accepted ones) and involve these new systems, then the northern portion of Seoul could be saturated with fire. Even areas south of the Han River could be within range of 170-mm self-propelled guns, 240-mm multiple rocket launchers or 300-mm multiple rocket launchers, depending on their position on the North Korean side of the DMZ. If every one of Pyongyang's 300-mm multiple rocket launcher systems were directed against Seoul, their range would be sufficient to rain fire across the city and beyond. A single volley could deliver more than 350 metric tons of explosives across the South Korean capital, roughly the same amount of ordnance dropped by 11 B-52 bombers.