Don't know if you'll find it helpful, but here is my
Atlas build (or something like this).
I get close and override my heat (as long as I have a target in front of me). I typically aim for a single target, and try to be sneaky. If I need some range, I shoot with my LLs (which can be changed to ERLLs if desired, but be careful of heat when you start to brawl). I've found 3-6 alphas (depending upon the mech and the friendliness of Hit Registration) kills just about any target I crash into.
Also, if you have a team behind you and you are pressing through a choke point, DON'T STOP. Keep pushing in. Even if you die, if your team is behind you, they should finish the push and kill whomever was killing you. But, you have to know when to charge forwards, and also a bit of hope that your team will follow you when you do charge forwards.
My main statement on your build from what I can tell is, if only short range is being a problem, them maybe place some longer ranged weapons on to support while you close the gap? For my mech, it's the LLs that let me deal some damage, even if minor, to the enemy till I can really reck face. They aren't a primary weapon, and I don't play to just them. Sometimes, one needs a little balance to make a mech work.