A bar sight is a rear sight that consists of a movable bar supporting an open notch or peep aperture.^1 2

related:

• • • sight, aperture
    • sight, iron
    • ..

1. This term is referred to in, but not defined by, “Glossary.” ⇒ﾠ Sporting Arms and Ammunition Manufacturers’ Institute.ﾠEd. SAAMI’s Technical Committee. Web. 15-18 Jan. 2011.
2. The author is a graduate of the Pennsylvania Gunsmithing School’s Master Gunsmithing Program.