Hello GT, I am currently looking into purchasing a Eotech HWS for my AR15. This will be my 1st optical sighting system so I want to make sure that I get something that I like and that I can be proficient with. The sight will be used for range practice close/long range, tactical range courses, and civilian self defense. I want to have the aiming recticle of the Eotech as clear and unobstructed as possible; I do not like to co-witness even though I do have BUIS's but, of course that's a must. I don't think I have much of a need for a NV compatible version because I do not even own a pair of NVG's so I think I will opt for one w/o NV capabilities. OK so with that said here are the Eotech HWS I am considering: Eotech 552 Eotech 516 Eotech 556 I believe the 516 is raised 7mm so that it puts the Iron sights a little lower in the window but I have not tried any of these in person. Basically I need to know what's the differences between them and which will sit higher so I can have a clear view w/o co-witnessing. Also any opinions are more then welcome' pics are too! So, which one should I get? Make suggestions too, it doesn't have to be the ones I am contemplating on getting. Thanks.