Despite being mechanically declined (I saw something twice and it's still too short...), I managed to assemble a lower.
The upper is my dedicated long-range/varmint gun: 20" free-floated fluted barrel, side-charging upper from a Phoenix area company that's out of business now. The Fealty Arms lower has a Geiselle trigger, Ergo grip and Magpul PRS Stock, and the whole thing is capped with NC Star optics and hardware that I need to replace with better stuff.
So, suggestions for a decent sub-$400 long-range AR optic, ideally with a mil-dot reticle?