The blast will encompass the whole head and a few meters more if it hits dead on. (@Ace).
OOC: essentially, a micro-Nuke.
IC: "You guys, get clear now!" Seraphicon yells, realizing how powerful the blast is likely to be.
A deafening KABOOOOOOOOOOOMMMMMM!!!! erupted from the blast as the missile detonated, completely destroying the missile.