I had some exactly like that. If you are considering getting rid of them. Think about donating them to a local outfit that does military honors funerals as they have to buy them for the 21 gun salute.Those are blanks? Well I'll be.
Curious as to what caliber they are. Here's a pic with a 7.62x51 resting on top.
View attachment 27712
Case dimensions appear identical. I think they're 308's or 7.62x51. Hell I don't know.