Another nice big boomer for you buckstix. The scout scope mounting is an interesting one. A couple of images of Hannibal rifles in an old A-Square catalogue I have, one with the Coil-Check wood stock and the other with the synthetic stock option show both with scout mounted 2x Leupold EER scopes. The scopes are mounted with the objective lens level with the back of rear sight base and the ocular lens further forward over the receiver ring.
It seems the 2.5x scope (make?) on your Hannibal is a different setup. Would it be an original scope and mounting by A-Square for a client or a later addition by an owner?

Not sure where the objective lens itself is positioned in the tube but wouldn't be ideal if at the front of the tube under the ring. Would need to be careful not to crush the lens if ever tightening the ring. Has been known to happen.