[davetex]

http://www.primaryarms.com/anderson-manufacturing-am15-with-fixed-front-sight-am15

Still in stock.

[Lurkinanloomin]

I got a Diamondback just like that for about the same price.
I added a handle/rearsight for $16.00 and it’s ready to go.
If at any point one wants to dress it up, it’s a good building block. All milspec, which I understand the Ruger AR556 is not, so interchangability of parts might be an issue with the Ruger.

[huntingtime]

Yes, I really like that Anderson actually. Threw it in my gun safe that i found here: https://buyerbenchmark.com/best-gun-safe-under-1000/

Best of luck folks