I have used a saddle mount on a shotgun before (don't remember what brand of saddle mount). The mounts are easy to install, just push the trigger group pins out, mount the saddle mount, and install the retainer screws. Accuracy is only so-so with that approach because of the sloppy barrel-action fit. You can improve accuracy by pinning the barrel to the receiver, but then you are talking machinist time. Or, if this is a dedicated slug gun, you can epoxy the barrel to the receiver.
A better alternative might be to buy a slug barrel with a pre-attached cantilever scope mount if you can find one. Accuracy issues are non-existant because the scope mount is attached directly to the barrel. Added benefit is that the shotgun will retain its versatility as a bird gun if so desired.
Last edited by Scorch; August 3, 2012 at 04:24 AM.