Tried two of them with no luck - Sightmark Mini Shot Reflex Sight SM13001

I purchased one of these to go on to a Ruger scout rifle. The first one I got could not hold zero and when the elevation was adjusted sometimes the windage would move. So I sent it back and thought maybe I just got a bad one, so I returned it for another of the same. The second one was just as bad. Sent it back again and purchased a Burris FastFire III, much better. You get what you pay for!
Pros: Small & light
Cons: poor quality & One of the bad things about it is there are no positive clicks when adjusting elevation or windage

This review was written in the old system and had content requirements that are different than reviews written today.