It can feel odd at first to be running the different ballistics, but this is meant to be fighting at 200-300m, where it's less of an issue. With cooldown skills you can also fake a RAC by chainfiring the UACs until you jam~ Also if it be your preference you can swap a ML for an extra DHS, and run it on a 3R. But it's actually fairly fun to play and it can dish out pretty decent damage if you don't use the lasers too much until stuff is open.
Be mindfull that smurfy does not take into account double taps, so this build is gonna be really hot, especially for a brawler role like it was suggested in the OP. As Remover of Obstacles suggested, Light Ferro could be a straight upgrade and since this build rely primarily on ballistic for the sustained DPS, I would drop a ML in favor of either a UAC5 ton of ammo or a JJ: the former is needed because UAC5 has less potential domage per ton compared to UAC10, the latter could be usefull for quick turning.
Actually I did end up with 4 lasers and an extra DHS is what I must have put on because when I toggled Light Ferro I was at 80/78 slots used. I probably could go for another ton of ammo though. I ran out at the end of a match on Caustic and got an assist on the final mech using my 2 remaining lasers, but I did a lot of poking and using the ACs since it's a hot map to begin with. Thanks! I still haven't gotten into the habit of using Light Ferro.