Grendel AR upper build vs bolt action accuracy

[biodsl]

What would it take to build up an AR Upper with a similar level of accuracy as the others, ie something 1/2-3/4" at 100 yds with good handloads tuned to the rifle. Is this realistic to expect from a semi auto AR upper for under $800?

I read this whole thread and would like to re-state what others have said but make sure it's clear: this requires a top tier barrel. There won't be much left over for an upper receiver, gas block, hand guard and bolt carrier group.