HOT TAKE so, you want to build a mech that has a ideal 400m range. Here are a few ideas/suggestions. First, forget about IS TC with missile builds that don't require lock. It's a ton wasted, and only used to help you lock on to targets and buff ONLY the PPC. Second, just use dual AMS, so you don't have to manually toggle the LAMS. It will also save you having to manage the heat from it. Third, strip your armor a bit, and it gives you an extra .5 tons, and that gives you more options. With this in mind, I came up with two ideas. Either go down to 2xMRM10 so you can gain speed, or up to 2xMRM20 for some more firepower. yes, I know this first build uses IS TC, but you can use that a faster lock time, or swap it for more ammo.