Cleaning up my shop. Military left overs

[Chuckie]

Well, considering that it would be made out of recycled .50 cal cartridge cases, I was thinking more along the lines of :

 

[Ians 17/22]

Found these while cleaning my shop. Old .50 cal cases from my days in the military. Had no idea why I kept them but I am sure I had a reason. Anyhow I am trying to find a cool use for them. Any ideas?

Dad made these during the war (1943)