Language Lessons: Window-Licker’s Guide to Sight Cowitness
Also Known As: Co-Witness
Applications of Use: Shooting rifles or pistols that are equipped with both iron sights and optics in-line with each other.
Definition: The ability to align and use your iron sights or BUIS (Back Up Iron Sights) through the lens or body of your primary optic.
Why it Matters: If your red dot breaks, runs out of batteries, or otherwise becomes out of commission, cowitnessing sights allow for nearly instant transition to a secondary sighting system.
Into the Weeds: This Language Lesson is primarily focused on use with 1x red dot sights (RDS) on rifles. However, some aspects absolutely apply to pistols equipped with a RDS. As LPVO’s (Low-Power Variable Optics) increase in popularity and red dots get more reliable, conversations about the importance of cowitnessing have waned, but it’s still important to know the ins and outs.
There are two main types of co-witness that are normally referenced: 100% (or Absolute), and Lower 1/3rd. With that said, there are a lot of nuances at play.
With 100% or Absolute Cowitness, the point of aim with the iron sights bisects the middle of your RDS. Since modern, quality red dots have minimum parallax (none of them are parallax free) one can look over the top of the iron sights and still acquire the dot relatively unobstructed. If your BUIS are zeroed at the same distance as your red dot, when you look through your BUIS the dot should very closely align with them.
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