Some in the "tacticool" crowd insist that their AR's be built to military specs, so their chamber just has to be 5.56 spec, because it's a gun their life depends on, though I imagine well less than 10% of the "working" guns are used for that.
As to .223 chambers, many shooters are only going to put commercial .223 ammo through their guns.
For your application, the wilde is the best way to go.
