Yeah, Whitewigt is right , go to episode 4 solo quest in ultimate and do the quest " the restless lion" in solo mode.
You can find there a demon raygun with hit easily, and since you are a hucast , you shouldn't have any problems with the hunters there , if you use your traps correctly.
The only problem with using demon and being a hucast, is that the special is lowered to 50% hp cut . (instead of 75 % for fleshies).
You can also find other good weapons in this quest , like charge vulcans, charge arms , hell raygun , arrest raygun, charge diska etc......