OK, well I finally got through the about 20 gallons of cosmolene packed into and onto this rifle. It's a 1916 made Mle.1907-15 Mannlicher-Berthier in 8x50R Lebel made by Établissement Delauney Belleville. Delauney Belleville was a Luxury Automobile Maker (Limousines - one is featured when Kate Winslet is ravaged by Leonardo DiCaprio in Titanic...) that answered the call in WW1 and switched production over to making arms and munitions for the French Army during the war. Of the two Établissements (private companies) that did so (Continsouza and Delauney Belleville), Delauney Belleville was the only one to make complete rifles, Continsouza only supplying receivers and small parts. D-B is the rarest manufacturer of 1907-15 rifles. They are very uncommon as Berthiers go.
This one has been rearsenalled, like nearly all Berthiers still in existence. It has not been converted to the later Mle-M-16 pattern, but has received the Balle N chamber and sight upgrades. The stock has been arsenal renumbered matching and the bolt is, sadly, mismatched. Berthier bolts require partial disassembly to remove them though, so I suspect it was fitted at the time of the sight upgrades. In the late 20's onward, FRench arsenals stopped force-matching replacement bolts.
All in all, this is a great August acquisition for me as I've been chasing a clean D-B Mle1907-15 for a long time

A HUGE thanks to the CGN'er that sold it

- You know who you are!
Did I mention the bore is about perfect?
Now to go rewatch "Beau Geste", "A Very Long Engagement", "All Quiet on the Western Front" and my personal WW1 French favorite, Stanley Kubrik's "Paths of Glory".