Forty buck Berthier

I know an excellent video that might answer your question here:

Forgotten Weapons with Ian McCollum: The Berthier Gets an Upgrade: The Model 1916 - YouTube

rare colour photograph of French colonial (Senegalese) troops. They are keeping their Berthiers (or Lebels) clean with a sock with the toe cut off, and some sort of muzzle cover too. Just on the edge of the shot is a Chauchat machine rifle, with its action cover in place. Alsace, June 6th 1917.

https://www.milsurps.com/images/impo...standard-1.jpg