Are there any ammo collectors here? Where would the best place to sell some? I have come across a box of 460 weatherby by hornady. box has elephant on front. 500 g

for something like that, you can try looking for some ammo's forums, or maybe even a weatherby forum
places like Armslist com , will have free on line add you can place, and gets a pretty good amount of action
local gun shows too , you might find ammo booths
BUT your not going to get the best offers I think at a gun show, too many are there to buy and flip things IMO

gun show;'s are NOT as they were 20 yrs ago, when deals could be found

I don't know HOW rare your ammo is

but if its on the real rare side of things, some of the better high end auction sites can maybe get you top dollar
as a few do tend to auction off high end things and have a loyal following of buyers with deep pockets!

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

Considering that you can still by 460 WBY ammo I doubt it would bring enough to make it worth the trouble of trying to sell. This place has it for sale right now for $150 a box.
https://www.ableammo.com/catalog/che...658_14878.html