Using Red Dot Sights Red-dot sights are so overwhelmingly popular with the NRA "Bullseye" shooter (and also IPSC shooters) that a word or two about how to use them seems to be in order. Using these sights seems almost like cheating to the International event shooter who is restricted by archaic rules to using "iron sights" with their Patridge configuration of square front sight and square notch. The problem of being able to focus on only one element - front, rear or target - makes the use of the iron sights an exercise in discipline and frustration. All this is avoided with the various electronic "red-dot" sights - the target and the dot appear in the same plane. When zeroed, wherever the dot is on the target when the shot is released is where the bullet will impact. And, because the eye/brain is naturally wired to seek the center of a circle, there is a noticable reduction in effort when using this sight. Putting the dot in the center just sort of happens by itself! But, many questions are common when starting to use this system - How big should the dot be? How bright? Where do you focus your eye? Dot size is pretty subjective, but my experience has led me to choose a size that is approximately 1/2 the area of the black aiming area of the target for bullseye pistol. Smaller dots seem to lead to the tendency to obsess about "getting the dot perfectly in the middle" - sort of like trying to get the "perfect" hold with iron sights - and forgetting to release the shot smoothly while letting the dot (or the iron sights) "float" in the natural hold area of the day. Some red-dot sights allow you to choose between dot sizes, but in general there seems to be two popular sizes: about 3 - 3 1/2 MOA or about 7 - 7 1/2 MOA. I like the 7.0 MOA dot such as provided by the excellent small "Docter" sight we use on the Pardini GT45s and FWB AW93s. When I tried a red-dot on my AR15, an interesting situation became apparent. For "house-clearing" tactical work, a large dot was quickly acquired and was sufficient for close up "hosing" or even precise head-shots at 50 yards. But, in trying to determine the zero and grouping of the ammo used at 100 yards a MUCH smaller dot was needed. So, obviously, application is a major factor in choosing dot size. For the NRA outdoor pistol shooter, the 7 MOA is probably best.
Brightness is also subjective, but I recommend using the lowest intensity setting that gives good dot visibility without straining to find it as this will also give the roundest cleanest dot without "rays" emanating from the edges. When in bright sunlight, many sights can be fitted with a dual polarizing filter that allows you to diminish the incoming light to a less dazzling level. These are usually just cheap pieces of diffraction grating film and image quality might suffer, however.
Finally, focus on the dot. This is the part of the equation that is moving and the part you can control. The target is not going anywhere or moving at all and you have no control over it. The subconscious mind will analyze the dot's movement and coordinate it with the continuing smooth motion of the trigger release to give you that wonderful "shot breaks just as dot gets to center" experience. This is such a great way to shoot that one can only hope the fossils at the ISSF will soon come into the modern world and allow these sights on free pistols, air pistols, etc.
Don