Might have something to do with the barrel and barrel extension being one piece (when purchased), so its pretty impractical to “fix” headspace if it isn’t set correctly. Little different than actually pressing in a barrel and setting headspace on something like an AK, FAL or HK style gun.Funny how everyone worries about headspace except for the AR platform
I'd venture to say 90% of all assembled AR's have never been and better yet those that assemble them don't even know what it means
Now that that has been said what would you do to remedy it if there were an issue?
Long and short if its made to specifications no worries, if not you are just fireforming cases.
the design really doesn't matter.
And don't get me started on 5.56 vs .223 as it's another NON ISSUE