it would have to be a policy category that they created.
its not really a stretch, my gubs in my house are covered as property under my homeowners insurance any way
it would be a liability coverage just like with cars
discounts available based on make model just like cars
characteristics of the owner etc.
it can be done.
I suppose the question would be - What would the premiums have to be like to cover the spread on an accidental or deliberate shooting using the insured gun?
No way I can see this being underwritten by Llloyds or any other insurance company underwriters unless the premiums are ridiculous.