I dug a piece of .41 Swiss Vetterli Rimfire brass out of a residential yard this evening. It was about 5 inches or so down and sounded kind of like a spluttery dime on my F70. Took me a while to figure this sucker out - my understanding is that ammunition production for this old surplus rifle caliber ceased in 1941. No headstamp, and the rim has two dimples because the Vetterli rifle bolts apparently had dual strikers. I thought it was pretty cool.