It seems to me like Aurelia is the best AR user in TPS. Her skills nullify all of the issues ARs have; poor accuracy (under continuous fire), low fire rates (on some), lowish damage (on some), and decreased crit (sans Jakobs) mean nothing to Aurelia.
-Being able to freeze enemies easily means her ARs get a constant +200% critical hit boost, along with the 60% (even more accounting for All Glory to the Master) she can get from her skills.
-Large Caliber makes it so that bullet hoses like Vladof and Scav take less bullets to kill things. The decreased mag doesn’t effect those guns as much, and the increased damage can even redeem a decent parts bandit AR.
-Duchess makes the poor recoil and sustained accuracy of ARs a moot point. At high enough stacks, they can start looking a lot like Hyperions.
-QnQ and Podsnappery can speed up slow ARs such as Torgues, some Dahls, and some Scavs.
-Every weapon benefits from Wintertide, but ARs, being the fastest firing explosive and non-elemental weapons (from both Jakobs and Vladof) have a special synergy with it.
Overall, I think she may be the AR class in TPS. Even though they are looked at as an ammo diversity option in the TG, I think she has better synergy with them than any other character. Especially with Jakobs, Torgue, and Vladof (the shredifier demo in the TG thread looked the best to me out of the entire AR section).