NitroX,
Their #26 scope mount fits the Marocchi Finnclassic 512 after "rounding" the recoil stop slightly. The front lever lock of the mount only "half locks" the gun's integral base because the base tapers to the rib, at least at the 12 gauge barrels I have. This didn't created any mount unlocking problems after firing a lot of heavy slug loads.
The MAK mount that is designed specifically for the Marocchi is a more elaborated one but it cost me 6 times more.
Lefteris.