Artimis IV FCS

           If you use Artimis IV FCS, you must carry an Artimis system for each missile launcher you carry except for Streaks and DFMs. This does not become a burden unless you have more than 4 missile systems, however. Because the Artimis is not restricted by range like the NARC, it is better for use with LRMs.

NARC Missile Beacon

           The NARC system requires that you first hit the target with a homing beacon before your missiles gain the NARC bonus. Because of the NARC beacon launcher's limited range, it is not a good guidance system to use with LRMs. The advantage of the NARC system is that NARC guided missiles launched by any friendly 'Mech receive the NARC bonus. Therefore, a 'Mech can "mark" a target with a NARC beacon, and its allies can destroy the target with missile fire.