I shall throw the cat amongst the pigeons here...The hat COULD be part of Ernest Shackletons cold weather gear for the British Army...This COULD be be Russia, and part of the White army fighting the Bolshviks in 1919.
I cant make out the webbing.
Yes that is a cotton 50 round bandolier
I am away with work, and have no access to my books pro tem, so unable to give a fuller answer...