Wonderful mech! This one is Gauss HPPC synergy. The -15% ballistic cooldown quirk syncs the gauss (4.25 cooldown + 0.75 chargeup = 5.0 cycle) perfectly with the HPPC. With a bit of finger coordination you get 30 PPFLD just like a dual gauss setup. 4 ML are for damage amplification under 300 meters and against enemies under-running your HPPC. Use them only when the enemy is not shooting back, so you can twist like a champ and protect your XL-engine loaded torsos with the giant arms. Pro tip: mount the HPPC 2nd in the LT to place it at the highest hardpoint above the cockpit. and look at it! it is so cute! p.s. I actually run it with XL285 (I had it and did not want to spend cbills on XL280). Replaced 1 ML with ERSL to get the needed tonnage.
