You can make your lists and take pictures all you want to which is excellent for a robbery (for the police report and your affadavidit). I do as well. For a fire, make sure your insurance actually covers the firearms. You may have to purchase a separate rider for you policy to cover the current value of the firearms.
As the years go buy, you can amass a tremendous volume of valuable contents that may not be covered in a house fire. Things that come to mind are jewelry, art, firearms, sporting equipment, optics, cash, coin collection, gold and silver, computers, photography equipment, the actual pictures, knives, and anything else you like to collect that has concentrated value. So, if you really want to pay to protect these things correctly, you probably have to have a rider on your home owners policy that specifically lists these things and that friends can get expensive on a yearly basis.