A red dot, like a Strikefire, Aimpoint or Eotech seems to work.
I have put the Strikefire on a Vector V51 .308 and am more
accurate with that, than the factory sights.
i actually have a green laser on mine as well as iron sights. the green laser gets more use than my iron sights or my reflex. i just find myself shooting the pistol from the hip more often. looking through sights on a pistol is just awkward.
So far I have used XS Sights on handguns, rifles, and shotguns. I have been happy with the results on each installation. In fact I just installed a white stripe with tritium insert front blade on my brand new LE6920 that I got as a Christmas present.