There is an old saying in sales; "He who mentions price first, loses."
I want the buyer to make me an offer. If they don't have enough Chutzpah to make offers, what are they doing owning firearms? Just kidding, but really, if you are happy with the listed price, pay it and move on. If you really are interested in the item but the price is a little outside what you had in mind, make an offer.
Also, I would never list a price as firm. You automatically eliminate the buyers who don't want to negotiate. Sales is a numbers game, why restrict your customer pool by saying the price is firm.
You can be firm on the price, but don't say it. Just say; "I appreciate the interest, but my price is "x".
I agree. I think it's just rude to totally ignore someone when it takes all of 10 seconds to type "No thanks" and post a reply.