If you aren't concerned about the best possible price to flip short term as a massively risky short term investment, RIA auction is probably the best choice. The second would be Ruben, he's absolutely not going to make you a cheap deal but you will get absolutely exactly what he describes and he's super thorough. Completely good to go with 0 concern of being ripped off.
Rubens operation is
That might be the only fucking way I ever buy a Ruger. Not one but TWO transferrable Hannibal minis!?!?