🔎 UNIDENTIFIED Brass piece with threads/ribs

[ncsuwolf]

Need some help with this one….dug about a month ago, near Richmond at a house site dating from at least 1850s. It’s brass, fairly heavy, about the diameter of a penny. I can see things that remind me of a shotgun shell brass and the bottom of a light bulb…..but don’t think it’s either. It has had a run in with farm equipment in its life. Has the word “medium” (all caps) on the bottom. Can’t tell if the “rings” are threads or ribs. I’m at a loss. Any thoughts?

 

[pepperj]

Kind of reminded me of a small version of a thermos cork.

 

[Nathan W]

I've got something similar with "Avon Lite" on it. I think it's a lid to perfume or some other beauty product