Redfield used to make a base with a peep sight attached to the flat surface on the back of the base. Willis Fowler an Anchorage, Alaska gunsmith had some from various rifles. He would attach them to the appropriate base if he did not have one to fit your rifle. If you look up " Redfield Scope Base with peep sight" you will see pictures. If I remember it involved tapping two #4 holes on the back of the base.
Warne also made bases with an inbuilt sight.
I've had rifles with both types over the years. Only takes one scope failure to make sure you have backup.
Another option: Numrich has Redding shotgun peep sights. If you remove the sliding "peep" you can drill and tap the scope base. Deflection only but you can work with the front sight for elevation.
