I've been doing some browsing on various auction sites for C&R firearms.  I've noted in a couple auctions some rifles (SKS variants) that I would have been certain were C&R, but for which the seller was saying "I can't find this model on the list, so it needs to go to an FFL".  I've seen other auctions for weapons that the seller will ship to a C&R but which I don't see on the C&R List.

Who's responsible (in the eyes of the law) for ensuring that the weapon being sold between two C&R holders is really a C&R?  Is there liability on both parties?

Quoted: I've been doing some browsing on various auction sites for C&R firearms.  I've noted in a couple auctions some rifles (SKS variants) that I would have been certain were C&R, but for which the seller was saying "I can't find this model on the list, so it needs to go to an FFL".  I've seen other auctions for weapons that the seller will ship to a C&R but which I don't see on the C&R List. Who's responsible (in the eyes of the law) for ensuring that the weapon being sold between two C&R holders is really a C&R?  Is there liability on both parties?

Whoever holds the FFL, either buyer or seller or both.
The list is published by the BATF.
If it's not on the list then it's not a C&R.

Quoted: I've seen other auctions for weapons that the seller will ship to a C&R but which I don't see on the C&R List. Who's responsible (in the eyes of the law) for ensuring that the weapon being sold between two C&R holders is really a C&R?  Is there liability on both parties?

Non NFA firearms, 50 years and older, are automatically C&R firearms even if they are not specifically listed.

Typically the only C&R firearms listed are those LESS than 50 years old, and NFA firearms that are also on the C&R list.

Keep in mind, the C&R list has been growing since 1968.  That's part of why you'll see firearms that are clearly over 50 years old now, but are still listed because they weren't at the time they were added to the list.  They were found to be C&R either because they had some rare/collectible status, or because they used what was considered an obsolete cartridge that was not readily available in the US.  I don't think the obsolete cartridge is an ATF guideline, but I believe it was used at one time.

As to who's responsible, I agree that it's the person (or persons) with the FFL.  Though I tend to place more responsibility on the seller since there is no way for the buyer to absolutely verify C&R status unless they are holding the item in their hands.

I'm still puzzled by the non-C&R status of the recent Polish TT-33 pistols sold by AIM because the added safety modified them from their original configuration.  Plenty were sold by SOG (with the added safety) as C&R so where does that leave those?  My personal rule is that if I bought it as C&R then I can sell it as C&R.

LL