View Full Version : Rear sight aperture "bowl" on AR-15

November 21, 2009, 06:48 PM
I could conjure up some explanation - probably having something to do with gathering light I suppose, but I'd rather see if anybody does really know.

What is the purpose of the "bowl" surrounding the aperture on most AR rear sights?

I've seen them mounted both facing the shooter and opposite. That makes me think there are quite a few people that don't know its purpose.

November 21, 2009, 08:31 PM
Rear aperature holes have sharp edges. I assume the countersink is to reduce reflected light.

November 21, 2009, 11:08 PM
Less area inside the hole to fill with crud as well.


November 21, 2009, 11:12 PM
That "bowl" is perfect to fill up with water when you are shooting in the rain.

I realize that it is vertical when you are firing, doesn't matter. A big drop of water hits there and stays there.

November 22, 2009, 12:03 AM
I think that it's primarily to reduce the length of the peep hole. So your sight image is less likely to be affected by the angle of your eye.