My $.02: PSA is pretty dialed in on their small frame rigs, not so much on the large frame.
I've got a 16" 308 that runs and shoots well, but that's after 2 barrels with tight chambers before I got one cut correctly, adding an adjustable gas block and working with Sprinco to get the spring setup right.
I've got a couple 556 uppers that run great out of the box.
YMMV