At gunshows and on the web (eBay, Gunbroker, etc.) I keep seeing these unfinished lowers for sale. "All you have to do is have a machine shop finish it for you" is the pitch. Legal, or too good to be true? One guy with some of these on his table told me that the ATF regs allow a person to make "one gun a year" by and for himself. I can't find references to the legality of this anywhere. Anybody have the facts?

[Note to moderator: the following isn't intended to circumvent any law, but is an honest inquiry into something that I think might be quite legal to do if the proper law is observed. I am asking what the applicable law is in such a case.]
Or, for a more extreme but possible example, take an old Armalite demil AR-10 lower (original AR-10, select fire from the 50's), have it rewelded as a semi-auto and build a gun with it. The original AR-10 had no bayonet lug and the supressor could be brazed and pinned (I don't know if it was even threaded on) to comply with the ban. If you had a licensed firearms manufacturer (Class II?) do this for you and put his name and a serial number on it, it seems like this would be perfectly legal as it wouldn't be an "assault weapon" as per the '94 ban. I don't see that anything about such a project would violate any law, since the demilled lower would go from non-gun to a "newly manufactured" semi-auto. What legal hoops could be jumped through to pull this off?

Where can you get de-milled ar-10 stuff [>:/]?

A company called M-K Firearms did that with demilled M-14 receivers.  The BATF's position is "once a machine gun, always a machine gun" even if it was demilled and rewelded to semi-auto only.  They are currently going around the country confiscating all the receivers the company made.

Unless the machine shop is YOU it had better be a licensed firearm manufacturer, and follow the proper procedures (Form 4473, NICS and/or whatever your state requires) when the completed lower is transferred back to you.  Completing an 80% lower should be strictly a DIY project.



As far as I can tell that is a myth.  Neither the laws nor the regs have limit how many firearms you can make for yourself.  Just don't make one with the intent to sell it.  Start selling them and you risk coming under scrutiny.



I believe the Once-A-Machinegun-Always-A-Machinegun principle is in BATF regs and not the law.  The full-auto folks here know a lot more about it than I do.

I came across a demilled AR-10 receiver that a guy just had for sale along with a bunch of other junk. I noticed that the finish on the two halves didn't quote match, and then realized that the halves were  from two different receivers that had been cut a couple of millimeters offset from each other (mag well area) so that it might be possible to mill one down and reweld them into a functional receiver. I figure that since the original AR-10s were made in the fifties, this has been around since well before the GCA of 1968 and so if it just "turned up" who's to prove it wasn't done in, say, 1962? As for AR-10 parts kits, that stuff is around, too, though few and far between but not unheard of. I figure if I do this project and while I'm at it weld up the holes where the auto sear was, mill off all the little bits from parts like hammer, bolt carrier, etc. then refinish it nice and purty, why would such a gun be illegal? "Once a machinegun always a machine gun" unless it was a non-gun then a semi-auto. I'd think the BATF would have much more important things to do than chase down something they had no way to prove was in violation.

"Once a machinegun, always a machinegun" is not related to GCA '68.

Presumably one of the two halves would have a serial number which could be traced.  If you want to build an AR-10, you would be better off starting with a NEW partly machined receiver.  Search the Build It Yourself forum.  If you start with one 80% or less complete, the result will be off book and carry no risk of getting busted for an unregistered MG.