If buying a C&R eligible suppressor would it transfer on a F3 or F4?

Or would it be F4 private to C&R ffl then F3 to dealer to dealer?

Should be able to go straight to you on F4 (even if interstate). List your C&R FFL on the form.

If the buyer (you?) doesn't hold a C&R license then it's just like any other silencer transfer.

If the buyer is unlicensed then any FFL can receive it (tax-paid) and there's no need for any F3.
It does not matter if the seller holds a C&R FFL or not. (Only an SOT transferor can do F3 to another SOT.)

Ok that’s what I was wondering if a F3 would even apply to a C&R.

Tax Free Form 3 transfers are only eligible between FFL holders who are also both Special Occupation Taxpayers (SOTs), which are dealers, manufacturers, or importers of NFA firearms.

As a C&R FFL holder you can't pay for and hold a SOT status as a C&R license isn't eligible to be a dealer, manufacturer, or importer of NFA firearms.

Discussion about that here from 2017: https://www.ar15.com/forums/armory/Looking-for-Information-Regarding-CandR-Classified-Silencers-/20-481441/

I believe it would qualify, just like any old C&R MG, and I wouldn't count on getting a straight answer from ATF since they apparently aren't allocated any funding to determine such things.

If you're worried about any potential wasted time then have a regular business FFL be the transferee to receive the silencer interstate and pay the additional $200. Then do another F4 to the in-state purchaser.

If you want to try transferring straight to the C&R purchaser from out-of-state then do that. The worst that can happen is a denied F4.
(I'd include some kind of PDF document showing the age of the silencer in question.)

Im not actually buying anything at the moment just a what if type question.

I think C&R lic will become more and more desirable as the years tick on.

So in theory, anything made before 1973 (50 years old) should be C&R eligible right?