Pistol, rifle, carbine. I’ve always used
open (iron) sights for these activities, and I’ve shot both eyes
open for 50 years.
Majority of my focus is on the front sight. My eye acknowledges the rear sight, and automatically centers the front sight therein (be it notch or aperture), but my focus has always been the tip of the front sight.
Front Sight To Dominant Eye
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Front carbine sights are approx 25" from my dominant eye.