I've put together two AR-15s with .223 Wylde barrels. No problem at all, with 5.56 ammo. I too, will swear by their accuracy. As too replacing an existing barrel, I probably wouldn't go to the effort. But putting together a rifle from the ground up, I would.
The Wylde chamber does have tighter tolarances than stock 5.56. Means better accuracy, but won't function as well, if you're wading through rivers, and throwing the gun into sand bars or mud, at the edge of the river. I'm sure they'd do less well, in those, shovel sand into the open "upper" torture videos.....
