Is anyone aware of a rear iron sight for an AR (i.e. picatinny mountable) that adjusts similar to this:
It's difficult to tell from the picture on the page, but the hole in the peep sight itself is adjustable to increase or decrease the aperture. The virtue in adjusting the diameter of the peep sight is that you can adjust it to light conditions, with a smaller diameter hole for brighter conditions and a larger diameter hole for darker conditions. Most AR sights come with two apertures, but I like this "infinitely" adjustable aspect of the older Springfield style rear peep sights.
Also, for anyone who routinely shoots with irons, what front sight posts do you prefer? I currently have the Magpul MBUS, but I'm considering swapping that out at some point.