Fedex guy tells me I cannot ship firearms to myself w/o FFL by law

[TexasRifleman]

When do firearms parts actually constitute a firearm?

The safe bet is to consider the piece with the serial number to be a "firearm" whether it's functional in that condition or not. ATF defines what exactly a firearm is, take for example an AR lower pictured below: That's a firearm all by itself. And, if it's designated by the manufacturer as such, or has been built as such, possibly even a handgun.

All by itself:

 

[waterhouse]

For another fun example, this picture shows 2 firearms. It may just look like a couple barrels for a Ruger .22 pistol, but that is the serial numbered part and has been designated the "firearm" portion of the pistol. If you order one from say, Tactical Solutions, they have to ship it to your dealer and you have to fill out a 4473 to pick it up.



And this picture, although similar, shows zero firearms, because on the Buckmark the "lower" (the grips, trigger housing, etc) is the serial numbered part, and this is just a barrel. You can order one of these directly to your door (at least in most states; some states have a problem with the threaded barrel, but the point is that it isn't a firearm.)

 

[Art Eatman]

Enough wandering...