I have two 45-70 barrels that shoot particularly well on one receiver. One is scoped and the other is dedicated for a peep sight. These barrels have the Williams rear sight with the sliding ramp. Midway sells a peep sight for this base for $4.99. I purchased one as a backup in case I lost the one on my Marlin 1895 with the Ace-in-the-Hole setup.
I tried it on my dedicated peep sight barrel, replacing the factory leaf sight. It works really well. I am in my 60s and am hitting beer cans at 65 yards with this thing using the factory front sight. I purchased a couple more, and have one on my scope sighted barrel now as a backup.
If anyone is looking for a peep sight or backup for a scoped barrel, you may want to consider this, especially if you may be uncertain if you want to use a peep or not. It is a heck of a lot cheeper than a new Williams or a Skinner that goes in the scope mounting holes. The sight is not in the traditional place close to the receiver, but it sure works for me.