16.2mm Rimfire? (Probably not even a real cartridge)

I found this object at a flea market. I don’t think it is even a cartridge, but for 50 pence I bought it anyway.

“Calibre” inside of measurement of case mouth is roughly 16.2mm, case length is 60mm and rim diameter is 34mm.

It has the letters “HRH” scratched into the base. The rim/base part appears to be made from a separate piece of brass.

Does anyone have any opinions, or know this thing’s real intended use?

Thanks for any info.

I don’t know anything about it. but it is interesting. hopefully someone knows what it is.


I’m going to suggest this is most likely the end off a military swagger stick…

Another collector I know looked at this. Their suggestion was the bottom of a small oil can for a sewing machine or similar. They also said that they remember seeing similar caps on lubrication points on a steam locomotive.

That’s two possible leads that I hadn’t thought of.