Cartridge (w/headstamp ID tw 17?) Found on Former Army Base Land

Hi, I found this on a hiking trail on former army base land. I’ve searched but can’t come up with anything definitive. Anyone know about this one?



TW 71 Twin Cities Army Ammunition Plant, 1971.
Doc AV

Oh thank you Doc AV! That fits very well. I found it on the vast Fort Ord land on the central coast of California. The base closed in 1994. Here’s a pic of the cartridge. I am not at all knowledgeable so I have no idea of the gauge. Thanks again.

This should be a 5.56x45 M200 blank.