There is another approach that may work, depending on your marginal federal and state tax income brackets, and on whether you itemize deductions or take the standard deduction. Donate the items to an eligible charity (college shooting team, FFA, Boy Scouts, etc.) and take a non-cash charitable deduction for the current market value of the items. Up to $500 per donation, all you need is a donation receipt and some documentation of current fair market value (from eBay, auction sales, GunBroker sales, etc.). Over $500, you'll need all that plus a letter from the charity. Over $5000 in a single donation, you'll need a formal, professional appraisal of the market value. You can do the math, but in a high tax state like California it's easy to have a combined marginal rate well north of 40%, which means you net 40 cents on the dollar of whatever FMV you can establish. And you don't have to find a buyer for your stuff or pay fees to sell and ship the stuff. Another alternative, if you still want to sell stuff, is to split up the sales among different venues (eBay, GunBroker, this site, Auction Arms, local auctions, gun shop consignments, etc.), and keep the gross receipts for each venue under $600 per year. And split your sales between 2022 and 2023. Lots of ways to work the system and still stay completely legal.
Disclaimer: I am neither a CPA nor a lawyer, but I am an Interdisciplinary Obfuscator, so please take this advice as a guideline and follow up with a trusted professional. This is off the top of my head, and tax rules are constantly changing.
