A friend is using a 1300 for a bear gun. She had training with 870 with XS ghost ring sights and is trying to get one on the 1300. No joy.

What I have found for a solution is Williams sights, but brownells does not list a 1200 or 1300 rear base. They do list server bases just by diameter.

Does anyone know from experience which williams rear base would fit a 1300?