Well if you read Cope's original post about 5.45 they say that all 5.45 will not be imported.
"Confirmed from the IMPORT BRANCH of the BATFE...Just got off the phone with them....Exact words No more Imports of 5.45x39 Ammo....... Don't hate me as we are OUT OF STOCK ALREADY..... Just delivering the message..."
That is one part that is obviously incorrect, because ~99% of 5.45 is imported, but not all of that is steel core (I think the only domestic is the Hornady 60 gr V-max). The ATF AP ban would not have anything to do with the commercial silver bear or tula 5.45 that isn't steel core, but still imported. So at least part of Cope's statement is incorrect.