Hello Duke. In my day it was called a shooting box. Both ventometers and the scribe date near 1900-1914 era. If the .303 ammo is all round nose Mark II as is the packet then its the same era. 2nd pocket from left appears to be Mk I brass oil bottle. 2nd pocket from the right appears to be Mk II brass oil bottle. Centre pocket with bottle probably defouling liquid. 12 rds = 2 rds sighting, 10 rds application on target. The round pieced disc could well be an orthoptic - device attaches to shooting hat with disc folding down to act as aperture which may predate all other pcs. I used to keep a screwdriver, sight blackener with matches, pull-thru and flannel patches along with the venerable score-book with pencil. Once off the range you could keep odd ammo and junk (like bottle opener) in it. Mine was a government issue wood box with sling. JOHN