With the Grid Iron's 30% cooldown for all ballistics I found the LBX 10 works very well for this mech. Holding 100 round of ammunition gives a potential of 1,000 damage. Backed up by three medium lasers and a Cooling Efficiency of 49% lets you brawl quite well. Ammo amount is scale-able with this the addition of Endo-Steel and Ferro-Fiber. TL: DR PROS: Loads of Ammo Good Speed Good Cooling CONS: Low Alpha High Cost