You can buy a gun online, but it has to be shipped to a licensed FFL dealer. Where you will have to show ID to pick it up. It is a misconception that you can anonymously purchase a gun online.

that’s the fault of the postal system of not necessarily gun laws.

The armory was entirely a scam site :/ It’s wishful thinking to believe sending untraceable currency to a stranger online will actually yield guns on your doorstep. There was no form of escrow on that site, just scammers.