I think
this one just might reach your 'minute of wabbit' criteria, without modification, etc.
The Mini is what it is; a decent rendition of the M14 in a lightweight caliber, for those who prefer the ergos, etc. of that system. The 580+ Minis are indeed more accurate than they used to be. As an LE trainer I have spent some time at the bench zeroing various dept-owned M4gerys, etc. I don't think you'll see much difference in the accuracy of the improved Mini and your basic AR.
A HBAR or match built AR will give many bolt actions a run for their money, which means they'll outshoot the Mini. It's all a matter of 'what turns your crank' vs 'what you want to spend', vs 'what you're tying to accomplish'. If cheap mags and bolt-ons are your bag, by all means get an AR. If you like blue steel, wood and 'real rifle' handling, a 580 Mini and 20 round ProMags will do about anything you need to try with a 5.56 mm.
They're both good rifles. The above Mini goes in my unmarked car every day and out to 250 yards, I don't feel undergunned in the least. If they hand me an AR one of these days, I won't cry. I'll prove it and zero it and feel pretty well armed....or at least as well armed as you can be this side of a .308