I've only done silencer purchases from other dealers/distributors and then transferred to my customers in AZ. I have two buddies, both AZ residents who want to do a silencer sale to each other. AZ allows private party sales with no FFL. When I called ATF's NFA division, the man who answered the phone said, since they're both AZ residents, they can just Form 4 from buyer to seller, no FFL/SOT needed. Can any of you guys verify whether this is true? I've gotten suspect info from them before.

I sold an SBR to someone last year. Form 4 from me to him. It was actually surprisingly quick too.

If the transaction does not cross a state line, then no Federally licensed dealer needs to be involved to comply with Federal laws

Individual States may add additional restrictions

This is correct. It can fairly easily be done on eForms.

I do not know how long it will take to process but I think there may be some merit to attaching the original Form 1 or Form 4 to validate the transferror's ownership and maybe shortcut some of the research. I don't have a lot of faith that "The Registry" is well kept.

I purchased a Sig ModX9 from a friend.

He filled out the Eform, used my fingerprints, trust, and pictures (I have all that on a USB drive these days). and it was approved in about a week.

I did a private party SBR transfer when I lived in WA and 3 MG P.P.T. since moving to AZ in '01.