Oak Transit case

[things_green]

greetings, I have had this case for years and not, as yet, been able to identify it's purpose?

Beautifully crafted with cast bronze hardware.

the 2x hinges & clasp are stamped R^L

there are 3 instances of hard wood inserts that have been stamped, one with the Broad Arrow.
The one at the rear appears to have a name O.BROWN. which I found weird.
HM and a serial number.

The inside of the lid has a round relief bored in which leads me to think, Artillery Sight?

10" x 15" x 21" high

any insights appreciated.

cheers,
Brent.