Take a normal U or V rear sight and use a file on it to cut the angles to the bottom of the V.
Might take more than one front sight, (also made) to get heights correct for sighting.
These are typical front sights for this sort of rear sight.
In making the bead front sight for the bottom rifle pictured, I used a fine Swiss needle file to file a rounded groove in the top of a blade sight
then soldered a piece of round brass onto it. I cut the brass to the correct length with side cutters, then filed it to the tapered shape needed,
pointy end towards the muzzle. If the centre of the bead is just a few though lower than the bottom of the rear sight's notch, it will be about correct
for elevation, for most rifles & give a zero at 25 and 50 yards. It will be about 4" low, at 100yards.