Pull all of those Remington M-591 & M-592's back out of the closet fellas!

Old Western Scrounger( http://www.ows-ammo.com/catalog/product_info.php/products_id/1174 ) has 5mm Rem Mag rimfire ammo. It's made by Centurion.
Right now he's running a sale on it at $19.95/50.

Really good price, considering what it has been going for recently.