as TDC said...they are not milspec.
Unless you're in Venezuela, Uruguay, Paraguay, or Iran - then they are milspec.
I've had an early 14.5 and a late 10.5 upper - they worked fine with the vast majority of NA parts - I never had a handguard problem because I had a free float rail fitted. The major issue I had was trying to replace the ambi safety, the rest of the Stag parts kit worked just fine, and the Stag parts worked with the Norc safety, so not really an issue. As far as the receiver extension goes, you can swap it out for a milspec one, or buy commercial extension stocks, which ever you prefer.


















































