* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions. Vindicator is also an option, although don't expect it to burn through bosses. But besides Lancer or Harrier, I would go Saber, Valkyrie or Mattock.
By and large, I don't care for lot of AR's in this game since balance is all over place, and there is hardly any handle like you would expect archetype of class to handle. Needs to be level up to gain magazine capacity though. At any rate, if you think Lancer is bad, then that may be a problem since it is one of the better AR's in SP, at least in terms of DPS. If on PC, one of the best ways to improve SP is to get something like the expanded Galaxy Mod, which moves some late game pickups into stores. A glass case will rise up giving you access to Saber. Choose yes, then go to the opposite end of the hall and activate another red circle. There is a red circle you can activate that will then ask you if you want to manually override something or other. Saber can be found when doing Sanctuary mission in the last room with two brutes and banshee.