Powder flask looks like zinc to me, Tim.
A drop of oil may help it, as zinc flasks tend to oxidise badly at times.
These were made so long that it very hard to put a date on them. Anywhere from 1840 to late 19th century I would say.
If you give both a bit of a rub on the charger or tops, there could be a name of the maker, but if it says Hawksley or Bartram, or Sykes, they made millions for all that time period it seems!
I'd tend to lube the powder flask charger a bit to free it up., ensure spring and such doesn't rust further.
The charger will unscrew from the flask as this is a "fireproof" or patent top.
Back in the UK, these are usually kept bulled up bright, but here there are differing thoughts!