My first AR build was a Spikes Punisher lower with Rock River 2-stage trigger, Magpul furniture and a 300 AAC BLACKOUT upper. Optics I put on top was a Vortex PST 1-4X24 TMCQ on a GG&G mount along side the scope I have 45deg BUIS.
Now all I have to do is wait on the stamp for my AAC .30cal...