No serial number - what part is the firearm?

[cc-hangfire]

I was musing this morning, waiting for a doctor’s appointment to roll around, when this random thought crossed my mind.

If a firearm doesn’t have a serial number, what individual component is the firearm in the eyes of the law?

I have a few old long guns - Glenfield/Marlin Model 60, J C Higgins Model 20 - that were manufactured before 1967, and they do not have serial numbers (legal at the time). If I completely disassemble my SIG P250, the small serialized frame is the firearm. But if I completely disassemble my J C Higgins shotgun, there is no firearm left. Only parts. No serial number.

Practically speaking, I bought a replacement barreled receiver for the JCHiggins, and it was treated as a firearm with the normal FFL-to-FFL shipping. So civilized people strive to obey the law (me included).

But if I possess a bag of non-serialized, disassembled parts for a complete JCHiggins 12 gage as I drive into - say - California or New Jersey, do I possess a firearm. If so, where is it? (I realize state laws may differ from federal law on the definition of firearms)

And this is what happens if I have spare time to muse!

 

[deadin]

A serial number does not determine whether or not a part is a firearm. (If it did we would be filling out a whole lot more 4473's)
Convention holds that the receiver is the firearm and, after a certain manufacture date, must be serialized.
(Good luck trying to convince a judge that your JCHiggins isn't a firearm....)

 

[pintler]

18 USC 921 lists the definitions, and reads:

"(3)The term “firearm” means (A) any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive; (B) the frame or receiver of any such weapon; ...(list of other things)"

so to my amateur reading, it's a 'firearm' if it goes bang OR it's the frame or receiver of something that goes bang.

I suspect an actual court proceeding might look to general usage. For example, for AR's by convention the lower is the firearm, but for FAL's the upper is the firearm. If you had a home built AR lower with no serial number, I think you'd have trouble telling the judge 'it's not a firearm; my personal convention is to put the serial number on the upper'.

But what if you have a DIY one of a kind rifle where, as with the AR of FAL, it's a little ambiguous what part is "the frame or receiver"? That seems like a gray area to me, where 'gray area' is defined as 'if the judge disagrees you go to prison'. I think in that case I'd treat them both as possibly a firearm.

ETA: and I see Sam1911 posted 27 CFR 479.11 which defines

"Frame or receiver. That part of a firearm which provides housing for the hammer, bolt or breechblock and firing mechanism, ..."

which doesn't help much for, say, an AR, where the hammer is in the lower, and the bolt is in the upper or in the carrier depending on how you want to look at it, but might help a lot for a shotgun or bolt rifle where all those criteria point to the same part.

 

[rodregier]

If you're looking for a functional guideline, wherever the serial number was marked on later production units
would identify the specific part legally considered to be the firearm on earlier production units.