Could you define " all over the place" and what type of ammo are you shooting? Are you shooting off of a rest or bipod or?
Many things can effect accuracy on a AR, can you mount the scope on the upper receiver picatinny rail without the riser?
This may take a few back and forth posts here.
Hi perf barrels and bolts
8 twist, 5R, Melonite, Wylde chamber