According to Invalid Link Removed, he used light gauge strings (Rototsound RS66LB) on his Aria, but they speculate he used Rotosound flatwounds on "Kill 'Em All."
It would make sense for him to use the light gauge strings, because of all the bending he did during his solos.
It would make sense for him to use the light gauge strings, because of all the bending he did during his solos.