If I have a C&R, can I ship USPS priority mail as a "dealer?" If so, does it have to be only C&R stuff? I think the answers to my questions are obvious, but I get dealer pricing from MidwayUSA and other retailers even though I only have a C&R, so I thought this might be a way around it.
No you can't. A C&R license holder is not a dealer as defined by federal law.
Handguns can be mailed only by manufacturers and bona fide dealers and only between themselves (there is also an extremely limited exception for military, LE, etc., not relevant to this discussion).
The law:
Section 1715. Firearms as nonmailable; regulations
Pistols, revolvers, and other firearms capable of being concealed on the person are nonmailable and shall not be deposited in or carried by the mail or delivered by any officer or employee of the Postal Service. Such articles may be conveyed in the mail, under such regulations as the Postal Service shall prescribe, for use in connection with their official duty, to officers of the Army, Navy, Air Force, Coast Guard, Marine Corps, or Organized Reserve Corps; to officers of the National Guard or militia of a state, territory, commonwealth, possession, or district; to officers of the United States or of a state, territory, or district whose official duty is to serve warrants of arrest or commitments; to employees of the Postal Service; to officers and employees of enforcement agencies of the United States; and to watchmen engaged in guarding the property of the United States, a state, territory, commonwealth, possession, or district. Such articles also may be conveyed in the mail to manufacturers of firearms or bona fide dealers therein in customary trade shipments, including such articles for repairs or replacement of parts, from one to the other, under such regulations as the Postal Service shall prescribe. Whoever knowingly deposits for mailing or delivery, or knowingly causes to be delivered by mail according to the direction thereon, or at any place to which it is directed to be delivered by the person to whom it is addressed, any pistol, revolver, or firearm declared nonmailable by this section, shall be fined under this title or imprisoned not more than two years, or both.
18 U.S.C. 1715
From 18 U.S.C. 921
Definitions:
(a)
(11) The term “dealer” means
(A) any person engaged in the business of selling firearms at wholesale or retail,
(B) any person engaged in the business of repairing firearms or of making or fitting special barrels, stocks, or trigger mechanisms to firearms, or
(C) any person who is a pawnbroker. The term “licensed dealer” means any dealer who is licensed under the provisions of this chapter.
Here is the language from the Form 1508 a person must sign to mail a handgun:
"The undersigned is a manufacturer of firearms or bona fide dealer therein, and the parcels presented for mailing herewith are customary trade shipments or other articles for repair or replacement of parts. To the best of my knowledge and belief, the addressees are manufacturers of firearms or bona fide dealers therein."