Hello Tom! Normally they are imcompatible. These are the reasons: 1) The lateral hanging hole of FEDs normally differs (in all series) from Leicas. 2) The most afflicting problem is the final size of the bottom mouth in FED cameras. They even do not accept a cover from another FED camera! The high production level creates a new phylosphy of samples sizes and lots fitting covers to individual models. 3) the SCNOO latch must be readapted for the FED crate. 4) The axle must be remade on FED cameras in order to catch the SCNOO key 5) Finally the spool holding screw is left threaded on Leica and right threaded on FEDs, loosing it as you advance the trigger, becoming inoperative. Of course an skilled repairman can refit all the described items in order to the camera could be fitted to the new accessory, the same way it was born the FED Sport. Regards LP