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?

!

Steve

TW 71 Twin Cities Army Ammunition Plant, 1971.
.30’06?
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.