Not really from what I've read. That's according to Gun Tests magazine over the years.
They've tested lots of AR-15's. As in 13 of them since 2007, as well as 2012, 2013 and 2014. Retail prices ran from $845 to $1995. Most of them in the $1000-$1200 range.
How did they shoot ? Better than the two tests for the Mini 14, one of which was a 7.62X39, but not the 1 MOA vs. 4 MOA as some always post.
Using the same Hornady TAP 60-62 gr. ammo, the $1150 Stag Arms 15L shot 1.7 inches at 50 yds. w/ iron sights for five rds. The $1054 DPMS RFA2-AP4A Patrol did 2.2 inches. The $1534 Bushmaster Patrolman's Carbine shot 1.5 inches and the $1554 S&W M&P 15T shot 1.4 inches.
The $894 Ruger KMini 14/5 shot 1.8 inches. Again, all were shot with iron sights at 50 yds. multiple times.
Moving up to the varmit style AR-15's, and using a scope, and match quality ammo, the AR's did do better. But none did under MOA. The $1639, 10.5 lb. Rock River Arms LAR-15 Varmit A4 shot right at a 1.1 inch average with Black Hills 77 gr. Sierra Matchking HP's. But with Federal 223 62 gr. FMJ ammo, it shot 2.4 iches. With TulAmmo 223 Rem 55 gr. ammo, it shot 2.2 inches. And this with a Bushnell 4-16X50 Elite 4200 scope.
BTW, when they tested a $966, Ruger K-Mini Thirty-P/20, the found it shot a good bit better than 4 MOA. They got an average group size of 1.26 inches with WW USA 123 FMJ ammo, .85 inches with American Eagle 124 gr. FMJ ammo, and .75 inches with Wolf 122 gr. HP's. Again, these are averages of five shot groups at 50 yds. with iron sights.
Ah, yes. E