Phoenix makes one. As does warner tool (not sure if those are available these days).
I am looking for some info on whats out there for aperture sights to fit on a AR rail. Im looking for something that has 1/8 or 1/4 inch adjustments. Is there such a thing out there?
Thanks
If you can't find one with the AR Picatinny base, you can always buy a Lipski base from Creedmoor Sports - they have an adjustable side mounting plate so that you can get the proper sight height for your application.