Instructions
Identify the type of firearm. Generally shotguns and rifles are more valuable because of their size and craftsmanship, and because they are more complicated to manufacture. Muskets and flint-lock pistols are among the earliest and rarest of firearms, so they can be the most valuable of any firearm type.
Determine the manufacturer and model of the firearm. Most manufacturers stamp their name and the firearm's model number on the firearm, usually on the body near the grip. With this information you can contact the manufacturer to determine the age and rarity of the firearm. Older or rarer models will be more valuable than newer or more common firearms.
Examine the body of the firearm for marks of craftsmanship. These include etched designs in the metal, carved designs in the wood, fine materials such as mother-of-pearl or precious metals like gold or silver. Many reproductions are crafted to resemble antique guns, so these marks are not always a sure sign of value. While the manufacturer and model are essential to determining value, fine craftsmanship usually increases the value.
Determine the provenance of the firearm. Provenance refers to the history of the firearm from its manufacture through its various owners to the current day. For example, a 1911 Colt pistol is relatively common, but the Colt 1911 carried by Winston Churchill is among the most valuable in the world. Who used it and where it was used are crucial elements of a firearm's provenance. The longer and more storied a firearm's provenance, generally the more valuable it will be.
Judge the quality of the firearm by checking that moving parts move freely, that no parts are missing or broken and that the gun is free from excess scratching and wear. The more pristine the condition of the firearm, the more valuable it will be. While some guns may be worn with use, their excellent provenance will outbalance their physical damage and increase their value.
Check a firearm pricing guide for your type of firearms. These publications will offer a general guideline for the value of various firearms. Look up the firearm manufacturer and model and condition for an approximate price. These publications do not directly address provenance. Provenance value can vary and is best determined by an antique firearm dealer, or by auction prices.