I think I'd try consigning them with these guys:
RIA: The Finest Antique Firearms And Modern Gun Auction Company in The US.
They charge a fee, of course, but they have all the hassle.
'We Keep it Simple when You Consign With Rock Island Auction Company
Consigning is a decision with many concerns. It is our job to make it go smoothly and effortlessly. What you may consider overwhelming we handle as a daily responsibility - its our job.
• We keep the contract simple. There are no hidden charges for photography, insurance, etc. Our rates are some of the best in the industry.
• Getting items to Rock Island Auction Company is hassle-free. We are a Federal Firearms Licensed dealer. Items may be shipped directly to us or we can arrange for a pick up. Rest assured we will be with you every step of the way to get your items safely here.
• Once your items are in our possession and care they are stored securely and fully insured.'