Serious question: Does it really need barrels if the point is to throw a cloud of liquified metal in a large area at a falling object?
Metalstorm doesn’t throw liquified metal, and the range of liquified projectiles is generally measured in tens of meters. Further, no barrel/, no velocity, no multiple projectiles/cloud depth in a Metalstorm system, or you might as well just use a big Claymore, which would would actually be more effective in most cases per testing.