rail DRIVERS are not rapid-fire, or belt-fed, nor do they shoot balls. they take about 10 minutes to reload in real life, and they are about 30 feet high.
this is no glitch. two things can't be inside each other, so they shoot apart. about 1/2 of phunbox uses this principle. the perpindicular boxes are not crossing in the exact center, so they shoot to the side.
not much of a cluster bomb. cluster bombs have small bombs for shrapnel, so there should be two explosions. one from missile, and one for each piece of shrapnel.