Austria captured a great number of weapons from its opponents during WWI (particularly the early stages).
Many of these weapons were stamped AZF (Artillerie-Zeugs-Fabrik) indicating that they were officially inspected. Commonly found are Russian Mosin-Nagant M91 rifles and Italian Carcano rifles.
Mosin-Nagants with receivers bearing the inscription OeWG (Steyr) are also observed. I believe that the OeWG proofed M-N rifles were converted by Steyr to the Austrian 8x50R cartridge and at one time bore barrels which were also OeWG proofed. However, all examples I have observed have a Finnish replacement barrel in 7.62mm Russian.
The captured M-N rifles were traded to Finland in the 1920's and may also bear subsequent SA or other proofs. My understanding is that Finland had captured from Russia a number of Austrian weapons and arranged to swap them with Austria for the M-N's.
AZF proofed M-N receiver.