Our homeowner's insurance covers up to (I think) $2000 in total replacement costs. The do not offer a firearms rider. They "offer" to add additional policies for firearms, but want a different policy for each gun and I think it was $60 per year for each additional gun. It would involve a detailed description of each gun. I don't remember the details because it was insane.
I checked around and I believe that the NRA insurance is likely the easiest deal. With a membership, you have a certain amount of coverage and you can add (and pay for) additional coverage. For about $240 per year, you can have $20,000 in insurance. They'll want to hit your homeowners insurance first, then cover any additional loss. The nice thing is that the guns are insured wherever they are (car, campsite, deep woods, deep lake) and accessories can also be covered (some insurance might cover the gun, but not the scope, which actually cost more).
At this point, I have the minimum insurance and a really good safe. The real heirlooms (and all handguns) reside in the safe and my reproductions grace my walls. They go in the safe if we're going out of town. I'm taking a risk, but it's a calculated one.
CC Griff