Sam1911
Moderator Emeritus
I don't see why it would be a serialized part if Mech Tech made a Ruger mkIII conversion, is there something actually regulating that or is it just by manufacturer?
In the case of the Ruger, the part you'd be replacing (the barreled upper) is the firearm. The grip frame is just a part. If Ruger wants to sell a barreled upper -- THAT is a firearm, just like if they wanted to sell the receiver of a Mini-14 or the grip frame of a GP-100. If any other manufacturer wants to sell a Ruger Mk II style barreled upper, that part would be a firearm as well.
It all comes down to the specific design of the gun and what portion of it the BATFE has accepted as the serialized part. (See below.)
It would be amusing to have a gun made out of no "firearms" as far as the clever boys at the ATF are concerned. It would also be amusing to assemble two serialized "firearms" into one boom-stick ... can I mount my Ruger mkIII upper on a serialized lower somehow?
I think you're missing an important point. Federal law requires a serial number on the "firearm" -- that portion of which will be considered the "heart & soul" of the gun, so to speak. The manufacturer and the BATFE come to some agreement about which part that is. So, no, a gun can't be made for commercial sale that doesn't have some part of it seriliazed as the firearm.
As for constructing a working firearm out of two serialized parts -- yes and no, and yes.
Yes, in that some guns do have the serial number stamped on multiple parts (often european military arms are this way) but that has no bearing on US law. Only the receiver will be considered the "firearm."
No, in that no one is going to make a Ruger Mk II grip frame that is sold as a firearm by itself as such is unneccessary by law and would only add hassle and complexity. It would be like having your car titled with one VIN number and also having the frame of that car titled to you with it's own VIN number as if you owned two cars. (Two registrations, two sets of insurance, etc. )
Yes, in that in the case of NFA-registered machine guns, sometimes this does happen. Drop-in-auto-sears (DIAS) are registered as a firearm under NFA Title II. They are nothing but a small bit of metal, and must be inserted into a Title I rifle in order to work. Two serialized "firearms" working at the same time. Add a Title II registered suppressor to that gun and you could have THREE serial numbers. Odd, perhaps, but not outside the realms of logic.