Luger?

[butchd]

These mill markings are on a byf 41. Any info would be appreciated.

 

[Chipmunk6]

They are called waffenampts and are inspection stamps. Here's a paper on them, you'll have to scroll down aways to get to 655.
http://claus.espeholt.dk/mediearkiv/waae.pdf
HTH
Chipmunk6

 

[2152hq]

Eagle over #655 was used for inspection of arms produced at the Mauser Works.
Eagle over the swastika is the military test proof firing mark of the same era.