Link to wiki explain the rule with a list of things is disables. If what you are looking for is not in the list look it up in the wiki and it will tell you.
Electromagnetic Special Ammunition (E/M)
This is a type of ammunition designed to interfere with electronic systems through the emission of a powerful microwave pulse.
If a miniature receives a hit from E/M Special Ammunition he must make an
ARM Roll using his
BTS Attribute. If he fails the roll, all his Equipment and Weaponry, if vulnerable, is affected by the E/M pulse and enters the Disabled (DIS) state.
Ariadnian Heavy Infantries and troops that are not Heavy Infantry,
REM or T.A.G.s must make a Guts Roll when affected by the damage of E/M Ammunition. As an exception, those Heavy Infantry, T.A.G.s and
REMs which are Immobilized by E/M Special Ammunition cannot perform the Guts Roll.
http://infinitythegame.wikispot.org/Weapon_Chart http://infinitythegame.wikispot.org/Electromagnetic_Special_Ammunition?action=show&redirect=E%2FM