What kind/brand of AR did you shoot? You said you couldn't hit anything with it and mine is a tack driver. I ask, because the SGL series are one of the best AK's. if you're comparing it to a lower end dpms or Ontario AR, then it would be a very fair comparison. All things aside, I've never seen an AK outshoot an AR when it comes to accuracy.
FWIW I shot an arsenal SGL-20