I've owned, or shot several of the Ruger Americans including one ranch rifle in 5.56. Every one of them were way more accurate than a rifle that cheap should be. The stocks are flexy, but the way they are bedded it has no effect on accuracy as long as the fore end doesn't touch the barrel. That is easy enough with a generous free float.
The weak link IME is the standard 4 round magazines. The originals were rotary. They upgraded to a stagger feed 4 round mag that is a little better, but has still caused minor issues for me in my 6.5 CM if loaded with more than 3 rounds. Some of them take AR magazines, some Ruger Mini 30 mags, some use Accuracy International magazines. Every single one of those seem to work fine.
The magazine made for 450 BM is a single stack 3 round magazine. It also works great, even when loaded with 308, 7-08, 243, and 6.5CM. If you buy one in one of those calibers I strongly suggest buying spare 450 BM magazines for the most reliable feeding. They are only 3 round mags, but they work. Sometimes the 4 round mags don't.
