My $.02 - don't sell it, or any firearm, ever. In some states (particularly California, I imagine), it might carry legal responsibilities you might not want to deal with. Also, imagine when it really hits the fan - you might eventually trade firearms for food or other survival needs, so you might consider it an investment for later. Last, the M4 is a niche shotgun that you know goes for top dollar, so it'd be like selling a Porsche - it's possible you won't get your full money back for it even if you haven't fired it.
All that considered, and you still want to sell it, try Gunbroker.com, I see private sales on there sometimes. Some things to consider: you'll have to set up an account and to sell, complete the extended verification. Once that's done, Gunbroker charges a final value fee. Here is how you calculate your Final Value Fee: Take the first $250 of your final value and multiply it by 6%. If your item sold for $250 or less this is your Final Value Fee. If your final value was more than $250, take the additional amount over $250 and multiply it by 3.5%. You might try selling it privately (locally), but again, I imagine that's a real PITA in California and the West Coast in general.
Outstanding - pm sent. Thanks.
