Thanks Taylor- here's the front sight on my old 14 bore rifle that I may re-own sometime in the future. One thing I noticed about the mirage with these sights, even low on the barrel, is the distortion seems far less than a V and blade sight - less jumping around, minor movement. This may be due to the shallow angle of the rear sight.
Here's one for a round barrel.
And the rear sight that that accompanies the low bead on my old 14 bore. Note the point blank sight's notch height and the first leaf's notch height have little difference in elevation. If the bead is sitting in the first leaf, it is actually level with the 'wingtips' of the point blank sight. This works perfectly with the light 'target' load and with the heavy hunting load in perfect harmony. With target load of 3 drams 3F @ 1,225fps the zero is at 55 meters, the point blank sight & 4 1/2" low at 100 meters. The first leaf, OR holding the bead level with the 'wing tips' of the point blank sight gives a perfect zero at 100 meters and is 4" low at 120yards - thereabouts. The second leaf is the 150 yard meter for the light target load and third somewhere around 200meters, but it's hard to say - accuracy is gone by 120yards as it will only hold 4" to 5" at 100meters, compared to the hunting loads, 1.2" to 1.5" for 5 shots.
With the hunting load of 6 drams, the point blank sight is zero'd at 100 meters and about 4" low at 130meters. The first leaf is the 150 meter zero and the second leaf is 200 meters zero. The third leaf is zero'd at 300 meters for the 'long gong' we used to have hanging at that range. This rifle has never missed that gong, no matter who was shooting it. Seldom did anyone want to shoot another shot, though, the 'first' being the accurate one, was the one they wanted to remember. Neither the second nor third leaf have been filed out to the shallow V - just never got around to it as the little notches seemed to work OK for long shots.
In the picture above, you can see a little notch in the bottom of the wide V. I like this as the front bead seems to roll down to that small 'dip' and seems to lock there, never to come out - probably the easiest sight to use. For those who see a fuzzy front sight - the bead is more accurate sight picture. It is fuzzy around the outside, which enlarges the bead slightly, but the ball always hits in the centre of the bead - you don't have difficulty discerning where the ball will hit, like you do with an indistinct blade - where in the fuzz does the ball hit with a fuzzy blade?