Intriguing, though the notch is of typically too shallow depth:

[Linked Image from i.postimg.cc]

Compare that with the old, unfortunately long discontinued, MMC adjustable rear sight:

[Linked Image from i.postimg.cc]

The Novak adjustable rear sight, shown on the 4006 pictured in the originating post above, has also apparently been discontinued.

Sad times are these.


Every day’s an adventure.