Doesn't your homeowners policy already cover your guns?
If by "your" you mean "everyone who owns a home and pays for property insurance", the answer is "maybe, but more than likely not".
Home Property policies have limits. Most high value and/or high theft items have pretty low limits. Guns, furs (not really here much), jewelry, computers, collectibles, and so on have a limit of, say, $1000 per claim less your deductible.
To cover a modest gun collection valued at $10,000, a Rolex Watch valued at $7,000, and multiple PCs and Macs totaling $6,000, you might need to pay an additional annual premium of around $300 depending on the company for a "policy rider".
Liability is another issue. Most homeowners policies have about $10,000 to $100,000 in liability insurance if someone is injured on your property. Slippery steps, cracked sidewalk, rotten tree falls on the neighbor's dog, or whatever.
A gunshot missing the intended target and striking a passerby or neighbor in the yard could run up hundreds of thousands in medical bills, lost wages, and pain & suffering.
If you own a gun and carry it, or if you just have it handy for home defense, it's good advice to voluntarily have a million dollar liability policy.