Legal/AR question

[Apple a Day]

So I was at the gym last night, got on the treadmill, flicked on the tele and Sons of Guns was on.
Question: If you build an AR upper reciever to which the magazine attaches directly does that change the definition of the type of reciever, require serialization, FFL transfer, etc...?
They had a .50 caliber upper attached to an AR lower and got around the magazine well size limitation by just hanging the larger magazine to the left of the upper reciever like some enormous Sten gun (but bolt action). I was thinking that removal of that much support material right behind the chamber might not be a great idea for a big bore rifle but don't mind me.
Disclaimer: I don't own either an AR or a .50 caliber anything. I'm just curious.
Cheers

[Powderman]

Nope. Still an upper receiver. Doesn't need serialization or special handling.

As a matter of fact, I have been drooling at a Zel Custom Tactilite T2 upper for some time---but I have a Ferret (Spider Firearms) .50 upper on the way, so I'll be happy for that...for now...

[GoWolfpack]

Shhhhh, don't go raising these questions. Right now ATF says the lower receiver is the only part of an AR that is a "firearm." Unless the 50 cal uppers become very popular ATF probably won't mess with them.


The lower receiver still contains the fire control group, which might be the reason it's considered the firearm in the first place.

[Quiet]

The lower receiver still contains the fire control group, which might be the reason it's considered the firearm in the first place.

Reason why the AR lower reciever is considered a firearm is because it's the part that has the serial number on it.

Some firearm types (FAL, FNC, SCAR, ACR), the upper receiver is considered a firearm because it's the part that has the serial number on it and the lower reciever, which contains the fire control group, is an uncontrolled part.

[ants]

Yes, just as Quiet explained. Some guns serialize the upper, some the lower. Of course, some guns don't have split receiver (like a typical bolt action) so they serialize the one-piece receiver. Whatever part is serialized is the 'gun'.

Note: In rare cases a specific part is also serialized, like a Drop In Auto Sear, or maybe a Lightning Link. But that's for machine gun registration purposes.

[GoWolfpack]

So the receiver is considered the firearm because that's where they put the serial number. They put the serial number on the receiver because that's the part that's considered a firearm.


Makes perfect sense.








*Disclaimer: I'm only writing this to call attention to how un-helpful circular logic like this is. I know by this time to just accept whatever ATF JBTs say because they certainly don't have a concrete reason for it.

[KodiakBeer]

Some firearm types (FAL, FNC, SCAR, ACR), the upper receiver is considered a firearm because it's the part that has the serial number on it and the lower reciever, which contains the fire control group, is an uncontrolled part.

I can't speak to the others, but on a FAL the lower is the controlled part.

[Acera]

I can't speak to the others, but on a FAL the lower is the controlled part.

Nope, that is totally incorrect. The upper is the serial numbered part that matters. Most FALs do have numbers on the lower also, but they don't mean anything. The good news is due to this, the lowers that have the 3 position selector are not considered illegal in any manner.




(Sorry I just realized that I bumped a very old thread. Hard to believe it was still on the second page.)