Eduard Kettner was a gun dealer. The Kettner has an interesting mount for a scope. I would think it is a 11.15x60r which was popular (military cartridge)
G. L. Rasch was a German gunmaker
Victor Sarasqueta was a Spanish gun maker, apparently make high quality guns
"Victor Sarasqueta was a firm of fine gun makers based in Eibar, Spain. It mostly produced originally-designed quality side-by-side shotguns and double rifles based on British designs.
The business was founded in 1883 and in 1902 received a Royal Warrant as a purveyor of guns to the King of Spain.
After being reorganised as Victor Sarasqueta Rifles y Escopetas Especiales, S.A., the business became part of the DiArm Group in the mid 1980s, a company which did not survive that decade.
Other guns made by Felix Sarasqueta and J.J. Sarasqueta also exist, these manufacturers are related to Victor Sarasqueta."