Ok, I’m phoning it in this week. I found these old HK BUIS I thought I sold long ago, and I found that the old article on them has all the images missing.
On the HK416/MR556 and their .308 rifles as well the optics rail is higher than the rail on a standard flat top AR15. Because of this HK fixed iron sights are lower than standard height AR15 sights so they can not compatible to use together. Not that you would want too.
Under the 200m aperture of the drum, there will be 1 or 2 dots. If there is a single dot (like this one) the sight is calibrated for a 10.4 inch barrel. If there are 2 dots, it is the model for the 14.5 and 16.5 inch barrels.
HK Front sights are not adjustable, all zeroing adjustment is done on the rear sight.
The drum apertures are different sizes and set for 100 to 400 meters. The 100m opening is much larger than the other ones to make it easier to use for close quarters use.
Windage is adjusted by loosing the screw on the top of the sight, and turning the screw on the right side of the sight. 1 full turn will move your point of impact 6 inches at 100m. Tighten the top screw to lock the sight back in place.
Inside the drum there are two tabs. Compressing both tabs inwards allows for the drum to turn adjusting the elevation of the rear sight. You need to turn the elevation drum in 1/4 turn increments for 1.5 inch adjustment at 100m. If you don’t have the proper sight adjustment tool, you can make adjustments using a pair of needle nose pliers.
Zeroing these sights can be annoying.
They are nice sights, and if you are more familiar with HK style sights than AR sights, it is nice to have this option. However you can get good AR sights for cheaper that will have a finer and easier adjustments.