The size of the objective is not necessarily what will determine what ring height you will need. The ocular bell of the scope is where hammer clearance will dictate ring height. Some scopes have larger ocular bells, some have finger grooves for fast focus or power adjustment, some even have a piece protruding for power adjustment, all of this must be considered when figuring out ring height. All of my handi barrels had ring height determined by hammer clearance not objective diameter. Even my 32mm objective scopes require high or extra high rings to provide the necessary hammer clearance. Your best bet would be to take the gun and scope to the dealer and see what fits right in his shop. As a side note I have never needed extra high millets, I have a couple 44mm and a 50mm scope in high millets on handi barrels.