Bushie Prime is an honest to goodness support Mech, and that is the only way i've found it to be effective. If you support brawlers from decent range, you have a fair chance of surviving or thriving even if your teamates didn't survive the furball. To say that UAC10 is a brawling weapon is silly, I can hit ppl at max range with it(700m), if they decide to charge just let 'er rip! Actually, with the way its hit detection seems, that's my rule of thumb for UAC10, the Prime can hold a total of 150 AC 10 rounds, now that's a lot 'o boomboom! The only thing holding back the Prime is the LRM5s, which could be remedied with a scooch faster reload time, but not enough to bring its DPS too close to LRM10. AMS takes the majority out anyway.
The biggest problem with AC10 and UAC10 is that even when you are not actually hitting anything it still often shows an impact or explosion, I just train myself to listen for the hit tone, that way I know its doing its job.
It use to be a lot worse, one less LRM5, and only a an AC10.