Brass, about the size of a quarter.
I follow your thoughts on that, but most powder flasks (I’ve seen) have had flip tops or caps that attached vis chain. I haven’t seen any that pivoted. It is the right size though. 🤔Eyes don't like the pics. Or pics don't like my eyes.
Powder flask top?
It's less your pics than me. And then my imagination.Sorry the pics are causing you eyes discomfort. I’ll jump on that with a toothpick to see if I can get some more detail visible. Whatever it is, is mechanical. That part moved once upon a time
I may have spoken to soon….as usual according to the Mrs. I did a little additional cleaning……and maybe?They vary. A lot.
spouts are usually threaded on newer ones to allow swapping to one that tosses(measures) a different volume.
This picture shows a not unusual spring arrangement. Different that the o.p. one.
Lots of different flask types out there too.
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