Federal law provides that a regular FFL dealer who does not have an importer's license may import not more than 50 guns per year, however the guns must be for specific customers, not for resale. The law similarly allows C&R holders to import any gun which falls within the C&R definition, again, for his own use, not for resale. Additionally, such imports are exempt from the Federal Excise Tax of 11%.

I've looked at the regulations and it is pretty straightforward on the ATF Form 6 which is to be submitted and pre-approved.

However, my question is how does an individual navigate the Customs service when importing? Do you have to go through bonded warehouse, somewhat like game trophies? Or is there an easier way? Can an individual go to the Customs service with his approved Form 6 and "clear" his imported firearms himself?

I imported some rifles from Canada years ago. I didn't use a broker, customs cleared them for me and they were delivered to my dealer. That was several years ago so it could have changed.

I imported 4 rifles years ago from that nice gentleman in Australia that was ransacked by their gov't... At the time he put me in touch with a gentleman in TX that did the work for free for any NRA member...sorry I don't remember any other details.

I imported a Ralf Martini mini Hagen single shot
this past year. Ralf did the paper work on his end and sent me the paperwork I needed to fill out and I submitted it to BATF in Atlanta.
It took the BATF FOREVER to get off their butt and approve the transfer. It took them a long time just to put the info into their computer adn then they supposedly sent me conformation via mail which never ever arrived. After a number of phone calls I got the lady to fax me the ok and I then faxed it to Ralf. Once that was done I got the rifle via Fed Ex in a hurry. Of course all this paperwork took place during the shutdown of the govt, along with a snowstorm here and there. Yeas ago I brought in a Martini Cadet in 22 LR from Australia and no problems. It was a zoo this time but I got it and it is beautiful! You can see it on his website.
Better tomorrows,
Mims