Is the explosion of a meteor due to forces imparted to the meteor by entry into atmosphere, or is it due to heating of a meteor that contains water with conversion to steam triggering the explosion? Do chondrites explode more readily because of some water content than nickel/iron meteorites?
As a high velocity meteoroid encounters denser atmosphere, there exists an increasing pressure difference between its frontal and rearward areas. This plus the very high temperatures create the instabilities that ultimately cause the sudden destruction of the body. Chrondite meteoroids are more vulnerable to this type of destruction than iron/nickel bodies because of lesser strength.
I think the primary difference is tensile strength, not water content.