I did a "little" research on this one, so don't be afraid to let me have it.
Second, good luck in finding an FFL or company that will do the transaction.
Third, I'm talking about stripped lowers only. you will have to go with out the pistol grip or afix a 10 round magazine if you want to build it.
The banned (Roberti-Roos) list is very long, but not every reciever is on the list. the list specifies the name of the manufactorer and the the name of the banned rifles or receivers that they produce.
Some companies sale complete rifles wich are banned, but the "stripped lowers" they sale are not. The stripped receivers are "not" considered a model of their rifle line. They are considered "stripped lowers" only. They some times indicate this on the sereal number markings (ie, RG567645"S") that they were sold as a striped lower only, not as part of their "named" rifle line.
Now, if they have a " model name" on the lower that is on the banned list, you are S.O.L.
Or in the case of PWA, it indicates: PWA-"all." You are also S.O.L.
The above should keep you out of hot water if you keep it stripped or afix a 10 round magazine in the mag well and build it.
This should also allow you to purchase "certain" stripped lowers out of state or keep one if you didn't register it as an AW.
Just food for thought, go ahead and chime in with your thoughts, I could be missing some thing :)