You are building mil spec AR's for around $300? I call BS.
And arguing that a standard AK is as accurate as an off the shelf, GI issued Colt is ridiculous. On the Island, every rifle that the armorer issued was capable of qualifying at 500 yards, with irons. I am no AK expert, but I have shot a few and there is a reason it is widely accepted that the AR is much more accurate platform. Yeah, you can work on most rifles and improve accuracy, and everyone knows how reliable AK's can be, but modern AR's are pretty robust and I will gladly trade having to run a bore snake through the barrel every now and again for the ability to put every round into a torso sized target at 500 yds, right out of the box.
All of the research I have done puts Colt about middle of the pack, with Noveske and LMT as top tier. My best/ favorite AR is not a Colt, but a custom build, and the Ultra match barrel alone was more than $300, but it is almost boring in it's accuracy out to 300yds. I have never shot it at longer distances because 300 is the longest range my club has to offer.