What are the general rules on these? I know they will vary state to state. I live in Kansas (firearms friendly). Can these be shipped direct to residence, or do they have to be sent (if from out of state) to an FFL?
As long as it is for personal collection and not a business, it is legal to ship across state lines. USPS however has changed or changed a while back the policy for shipping handguns and no longer considers C&R legal to do so since it is not a legal business license. https://www.atf.gov/firearms/curios-relics
If you do not have a C&R license, they cannot be shipped directly to your residence unless they're 1898 or prior (antique). You can, however, ship C&R qualifying firearms to a valid C&R license holder if you sell one to them.
You also can't use your buddy's C&R to transfer. For example you buy a Lee Enfield on gunbroker, have it sent to your friend who has a C&R, then you go pick it up. Bad plan.
Yup, where ever you list your residence on the C&R, they can send the rifle. Cannot have a P.O. Box or APO, it has to be a physical address that you, in one way or another, inhabit, i.e. home or work. Or, workshop.
I forgot to add, the firearm has to qualify as a C&R by ATF standards. If the seller won't transfer to a C&R then you have to go through an FFL, simple as that. Fortunately, the ATF is going to the 50 years or older of known manufacture. However, if you have an AR-15, you have to have a way to show the lower is old, like a s/n that matches something 50 years ago. You can't slap a bunch of nostalgic shit on an AR with a lower that was made last year. That's gotta go FFL.