GunBroker.com now offers the ability to switch or convert an Auction item to a Fixed Price item at the time of relist. Any ended (sold or unsold) Auction can relist as a Fixed Price item by navigating to the ended item page and clicking 'Relist as Fixed Price'.
Or, navigate to your ended items in My GunBroker and click the 'Actions' menu and click 'Relist as Fixed Price'.
These links will land on the Relist with Edit page with the Fixed Price tab active. Please note that the system will take the BuyNow! Price to populate the Fixed Price value. If no BuyNow! exists then the system will take Reserve Price. If BuyNow! and Reserve both do not exist the system will use Starting Bid.