✅ SOLVED Brass musket nipple protector maybe? Help ID

[Southern Brass]

Not really sure what this item is . Its brass material 1 inch long from tip to base . its hollow on the inside with no threads. Only has one groove inside near the base. The top "nipple" is semi circle .It sorta resembles a nipple on a musket or flintlock. Any help identifying or an insight on what it could be is appreciated. Happy treasure hunting y'all!!!

 

[NOLA_Ken]

It's an old valve stem cap. The "nipple" has a flat side so you can turn it over and use it to let air out of the tire. Musket nipples would all be iron.

 

[Southern Brass]

Thanks !!!!