Optics with 34mm tubes are becoming more common but the selection of mounts compatible with them is still somewhat limited. Aero Precision has released new 34mm version of their excellent Ultralight Scope Mounts. These 6061 T6 aluminum mounts are their regular extended format and their SPR format which has 2″ of forward extension for optics with longer eye relief. They are also available in black or Flat Dark Earth.
Check out the 34mm Ultralight Scope Mounts at Aero Precision.