The problem with auctions is they charge a very high sellers fee. Most times you would be better off selling it yourself. If the ammo isn't antique they would be worth the going price. You can check here for vintage ammo.
http://www.gunbroker.com/Vintage-Ammo/BI.aspx. There are many other sites on ammo old and new n google. Here is one with an e-mail address where you can ask questions.
http://www.oldammo.com/contact.htm