Nothing cool about this build. Save your ATMs for good shots inside 550 meters. Use the mediums for dead zone shooting, knocking down UAVs or when you really need something to die quick (override - coolshot). Pick up heat gen and cooling skill tree nodes. At 63 kph - it is all about positioning, positioning, positioning. Alternate without LAP. Currently using this, with enough ammo for most matches with skills tree missile rack nodes.
Initial trial run with an extra heat sink and one less ton of ammo, but both missile rack skill points. Ended with 132 missiles left. Almost three salvos left. 6 kmdd out of 8 mechs hit. Did I mention that you can alpha without shutting down? Once. Even on Caustic.
You can loose the TAG also. You don't need misslelock to fire the ATM's. Just fire them like SRM's Bigger spread, same fun.
It pierces ECM - if you shine it a target in an ECM bubble, the target will eventually become lockable. It tightens the grouping of your missiles by a lot, focusing them onto one area It speeds up your lock time, and stacks with BAP, allowing for very rapid locks on targets It increases the tracking rate of your missiles by a lot, making them far more likely to hit fast targets For me TAG helps a lot and makes this build more lethal. The tighter grouping will secure kills and let you stay alive longer. You don't have a lot of heat to play with so make the hits count. Very perceivable improvement with killing lights. Your mileage may vary.