Upper/lower is the weapon?

[the_quark]

That really is quite an interesting question. But my guess is that if you put your slide on a different frame that the BATF would still consider the firearm with that serial number to be the gun with the slide which hold that serial number. To that extent I'd say that your slide is the firearm - but if the firearm is disassembled I don't know if the BATF would consider that slide to be a firearm.

You're more expert on this stuff than I am, so if you disagree I'll likely adopt your viewpoint.

Puts down the crack pipe

Upon further reflection (i.e., as soon as I woke back up after being up in the middle of the night), I recalled that the serial number clearly is on the frame of that weapon, and I was just factually wrong in my assertion that it wasn't.

Bottom line: Don't trust "experts" when they say something stupid.

[CSACANNONEER]

I could be wrong but the manufacturer may make a suggestion to the BATF and the BATF will review and approve it (or dis-approve). The one that bugs me the most is the Ruger auto, the barrel assembly is the controlled part. You can't switch barrels.

Thanx, Russ

It is possible to rebarrel a Ruger .22lr MKI, MKII or MKIII. In fact, I have a pre MK which was converted into a carbine. Someone installed a +16" barrel on it and a buttstock. So, it is possible to do. It's just not easy to do.

[CaliB&R]

Just a wild pair of guesses, 1) its what the barrel attaches to, or 2) what accepts the magazine or clip. I'm leaning towards #2, but I have never really given it much thought.

ETA: Ok, after a little more thought, both of my guesses can apply. On a 1911 or FAL upper, the frame accepts the mag, as well as is attached to the barrel. Now on ARs the mag well is only on the lower, barrel on the upper.

Could it be a manufacturing thing? Handguns are frames, US uses lowers, and world uses uppers?

[the_quark]

I think "where the serial number is" makes the most sense. I can't think of a firearm I've seen manufactured in the past thirty years that rule doesn't apply to.

[CSACANNONEER]

I think "where the serial number is" makes the most sense. I can't think of a firearm I've seen manufactured in the past thirty years that rule doesn't apply to.

Nope. I have SN on AR type uppers. If I put one on a homebuilt lower without a SN, it would not mean that the firearm now has a SN.

IIRC, I've seen federal guidelines which define what part of the gun is actually the "receiver". The funny thing is that the AR15 is completely bass ackwards. According to the guidelines I've seen, the upper SHOULD be considered the legal firearm.

[MoBait]

The lower receiver is bigger than the upper receiver on ARs

[cmth]

It's completely possible to fire live ammo with only a complete AR15 upper receiver assembly, yet it's not legally a firearm. The same can be done with most slide assemblies of striker fired pistols. Not that I would advocate doing so out of concern for safety, but it can be done.

[SVT-40]

The European standard is the "firearm" or controlled part is the portion which the barrel attaches to. Thats why FAL's, HK's ect have their serial numbers on their upper receivers. Same for eastern European AK rifles. The controlled part was the front trunnion and had the serial number engraved on it. The receiver as we call it was to them just a piece of sheet metal.

Because of US import standards many AK type firearms imported to the US now have their serial numbers also engraved on the sheet metal receiver as well as the front trunnion. Some like the Saiga do not and still only have the serial number on the trunnion.

In the US the standard to determine what is the controlled part has been where the fire control parts (Trigger, hammer, disconnector, sear Ect) are located.

Years ago when FN FNC 5.56 rifles were still being imported I received a large shipment of both 16" para type and 18" fixed stock rifles. Interestingly the 18" fixed stock rifles had their serial numbers on their lower receivers and the 16" para models had their serial numbers on their upper receivers.

I called FN and was told the reason for the different serial number locations was the manufacturing lines the rifles came off of. The fixed stock guns came of the "commercial" line and were intended for import into the US. So they had the numbers placed on the lower receiver.

The para models came off of the Military line , and although legal for import into the US, were manufactured to the European standard for serial number location. Meaning the serial numbers were place on the part attached to the barrel which was the upper receiver.