Got my lower(s) last week. Just some observations:
The take down pins seem to be oversized, since they're polymer I sanded them a little so they work a little smoother.
Every upper I've tried them with has been an incrediably tight fit. To the point I had to wack them to open them.
Lastly, the buffer tubes are commercial diameter, not a big deal unless you dropped money for a milspec Magpul replacement staock.
Now for the good news, they work like a champ. I used both a lightweight 14.5 and a heavy 16" upper and they both ran like w/o a hitch. I like the lightweight. Triggers are good. Internal components are quality.
I feel like a got quite a deal. Thanks for putting your offer on the High Road.
I only put about a hundred rounds thru rifles with the lower. As soon as I get a dedicated upper for one of them, I'll burn a thousand rounds and see how it goes.