I'm researching optics for my 17s with the goal of getting an optic that I can shoot both eyes open at 1x and up to 6x with one eye. The closest thing I can find are the Elcan SpecterDR and the ACOG. I would get the Elcan if it wasn't so dang heavy. One of the reasons I like my SCAR so much is because of the weight. Tipping it over 10 pounds sort of defeats the purpose for me. The other option is the ACOG except that it doesnt take a battery. I believe the concept of the ACOG is great but I hear complaints about it being worthless in dark situations since it's utilizing fiber optic. That leads me to my primary question 1) what is your experience with the ACOG in dark situations and 2) what are my other options?