You can ship any firearm to a FFL dealer.
UPS will normally ask to see a copy of the FFL for the receiving dealer, so have it handy.
USPS may or may not, but still have it handy.
I recommend insurance and a delivery confirmation (.80 cents) to document and track the package.
There is monetary reason some dealers require dealer to dealer. It creates two transfer fees for the dealer. One for the gun going out and one for the gun going in.
I just had a discussion with a dealer on the receiving end of a trade this week and he stated he had to have an FFL as it was federal law. We agreed to disagree and quoted him the law. In the end it came down to his transfer fee if the guy on that end found out he did not have to transfer it to the dealer to ship it out.
Here is some good info and direct quotes of law and off the ATF site.
How Can I Sell a Gun to Someone In Another State?
A very popular phrase in the firearms ads is "My FFL to yours." While that certainly would work, only one FFL holder is required, one in the state of destination. Here is the first question and answer from the ATF Site FAQ's Section:
(B1) To whom may an unlicensed person transfer firearms under the GCA?A person may sell a firearm to an unlicensed resident of his State, Only one FFL holder is needed, in the state you are sending it to. So if an individual in one state wants to sell a gun to an individual in another state, the seller is not required by law to find an FFL holder. Only the buyer must find one. Here are the steps:
if the buyer is not prohibited by law from receiving or possessing a
firearm, or to a licensee in any State. A firearm other than a curio or
relic may not be transferred interstate to a licensed collector. [18 U.S.C 922(a)(3) and (5), 922(b)(3), 27 CFR 178.29]
- The seller, for their protection, needs to verify the receiver is a licensed dealer. They need to ask for the receiver's FFL Number.
- The seller should then go to this website to verify the license and address: ATF FFL Ez Check Site.
- They should print the screen they get.
- They can then legally ship the gun to the receiver, but only at the address verified at the Ez Check Site.
- The buyer will then go to the receiver's place of business, fill out the forms and pass the background check.