I’m looking to purchase a new “red dot” for my carbine. Lots of them out there. I’ve looked at the Primary Arms Red Dot and I want to use it. Hence my lack of knowledge to the experts for advice. I also was thinking of adding a 3x magnification to it also. Do I need a riser on the scope? What about the 3x mag ? Searched the web, only to find that due to the distance from the top of the bore to the center dot, does not provide 1/3 co-witness. This setup is primarily for the AR platform. Hope I got that right! Anyone please feel free to correct my interpretation. Basically they advertise 3 risers for each. I just want to make sure I get the right combo. Thanks all.