Armory Parts Exchange, Inc. DBA APEX Gun Parts sells used gun parts without making a prior determination to the amount of use, wear, breakage, or alteration that may be exhibited in surplus/used parts. Variations within used parts are dependent upon the original manufacturer(s) for the weapons contract, the country of origin, the year(s) of manufacture, storage conditions, etc. Not all firearm parts are interchangeable; use of surplus parts without proper knowledge could cause a firearm to malfunction and cause property damage, injury, or death. Parts must be inspected and tested by qualified, competent, and professional gunsmiths or armorers before use in a firearm.