This build works best around 400m away, just pour all the weapons onto people. It once got me 1186 damage.
Not to mention 3 LRM10s are subject to heat penalty and won't fire in a single volley on hardpoints 2 and 3. I'd use a LRM10 + 2 LRM5 combo, and see of what I could do with the 6 tons. More AC ammo, AMS, CASE, slightly faster engine (at the cost of some armor on non-critical parts)... here's a suggestion:
Was trying to be less hard on hom, I would just use 3x LRM5 in that ase. Then again I prefer 3x SRM4 with the same tonnage. Less ammo needed, you can get DHS and upgrade to ERLL. But I think that is another build.
720 LRMs is indeed a low count for 3LRM10, you'd go through that in 2 minutes flat. I'd also look into 2LRM5+LRM10, for the 20 LRM alpha, and better rack size to ammo count ratio. As for bringing 2LLas 2AC5 on at Atlas... The fact you have to expose three metric barndoors worth of torso before any of those weapons are on target means you'll be losing trades badly, very often. Also, STD300 is a very slow engine. You'll be as succeptible as a DWF, and I'm sure you've been hearing them complain about being left behind all the time.