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FWIW,prior to the introduction of the bright fiber-optic sights, I used
Bright Sights High-Visibility gunsight paint, w/o any issues, for about 20 years.
http://www.brightsights.com/index.shtml
I still use the product on guns that FO sights are not available for.
The one thing I found, however, is that metal prep's critical - degrease the sight surface intended to apply the paint, and let it dry thoroughly before holstering/using.
YMMV, but I just clamp the gun in my bench vise so the painted area's level, and leave it there overnite to dry.
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