All Insurance policies - vary by State guys...so be careful about generalizations.
The typical sub-limit on most homeowners policies is for "Theft of Firearms" only ...( not typically for Fire, etc ) and it is often a relatively low limit, like $2,500 ..../ but remember you have a deductible as well on a homeowners claim ( $ 1,000 is common ).
There are a few companies that have no sublimit for Theft of Firearms ...but it varies by state, even with the same company....AllState & USAA both have sub-limits for Theft of Firearms in my state...in other states, by your notes, apprently they don't....
Most companies will give you two options:
a. Increase sub-limit for "Theft - of Firearms" from say $ 2,500 to $5,000..for a very small charge ( maybe $ 25 a year ) ...but it may also have a limit within it, of no one item over $1,000 or something....and the deductible still applies.
b. Schedule each gun - that you want coverage on. Cost varies a lot by state ...but in my area its about $ 18 per $1,000 of value. If you have several guns that replacement cost is $ 15K - then premium will be about
$ 270 a year - but there is No Deductible in most policies for Scheduled Items.
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Issue is "Theft" not Fire....so having a good safe is probably all you'll need. But if you travel a lot with your guns, have 4 or 5 guns in your vehicle - and stop for lunch - after a range trip --- that's where you're vulnerable. Theft of guns from a vehicle - is usually a homeowners claim - not an auto claim...
Scheduling covers them everywhere - for virtually everything....but you have to "schedule every item you want on there" make, model, serial number, replacement value - and there is no "automatic coverage" if you replace one gun with a different gun...and you have to remember to take one off, if you sell it, and put something else on - if you want it covered by the schedule.
You do not have to "schedule" every gun you own ....you can just do the high value ones....
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NRA insurance - and others ...may be ok / and it'll keep a claim off of your homeowners insurance policy...but every policy is different. You have to read the details...and be a smart consumer.
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Personally - I have a good safe. I choose to only schedule the guns that have a replacement value of over $ 2,500 per gun....to manage my costs...and I use my homeowners insurance because I trust them. But everyone should read their policy for sub-limits --- and call their agent...!