Since a clean/clear sight pic is desireable with the tanger, please keep in mind that you have two options:
1) Remove the rear barrel open sight, install a slot filler blank (bought or handmade), and zero/shoot/etc with only the tang sight.
2) Replace the rear barrel open sight with a folder (if it isn't already so), and then set the rifle up with TWO different zeroes - a relatively short range (say, 50yds) for the barrel sight, and a somewhat longer zero (say, 125yds) for the tang sight.
I've found that when expecting a short-range, sudden shot while using the barrel rear sight (tanger folded), if/when a longer, more deliberate shot opportunity arises, there's usually ample time to fold the barrel sight and raise the tanger for the shot.
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