My only advice is not to spend a ton of money on a green/red dot. Between a friend and me, we have bought and used a ton of them, ranging from $50 cheapies to $400 ones and to be blunt about it, they have all worked fine, the main difference is how long the batteries last. About the only cheap ones we haven't had at least one of are the ones made of plastic. I have Cyelee, CV Life, Holosun, Vortex, and several others, and they almost all cost less than $125. It's not rocket science, it's just a dot. If it holds the point of aim, it's fine. My friend has them on 5.56 AR's and 9mm PCC guns that he and his son are pretty rough with, and a couple of the optics look bad, with gouges and scratches on them, they still work. One hint, replace the batteries that come with the sights, they can be pretty old and we both had one that was leaking in the box before we even put them into the sight. I don't buy any more red dots, just green, I can see it a lot better.