Actually, it's about import: Someone, not naming the company, inquired about import of a 5.45mm pistol (AK variant)... Hacking down already imported items isn't the same.
Well, importation of a pistol and importation of ammo are 2 different things. While the request to import an ak74 pistol may have piqued the ATF's interest, by no means is that required for it to find that a certain cartridge "may be used in a handgun". I would hope the ATF would at least only look at commercially manufactured "pistols" rather than one-offs, but we have no assurance that it will and the statute does not seem to require that.