I'm looking at a German Sporting rifle with a SKOPAR B scope with see though mounts on it. It also has a set of off set single claw mounts on it. The front one is mounted on the rib a inch or so behind the rear iron/flip-up sight and the rear is mounted off the left side behind ring. I don't have pictures right now. They think it is chambered in 6.5x57. Was that a common pactice to have a rifle set up for to different scopes?