What does cowitness mean?

kc5gxc

If a scope rail maker says iron sights will cowitness with a mounted scope, what does that mean? That you can use either one as needed without removing scope? (my guess).

nunn

You guessed right.

nmyers

My understanding is that cowitness means that your optics & iron sights are mounted in the same plane, so that you are able to sight your iron sights through your optics.

There have been several makes of scope mounts with iron sights that are beneath the optics, allowing you to use either without removing the optics. But, this setup is not "cowitness" because they are in different planes.

Neal

givette

kc5: givette here. Similar to a military post type scope, except with co-witness, the post you see in the scope is your front sight post. Scope is set up to make use of the front sight as an integral part of the total sight system. I may have left details out, but that's the gist of the operation. Hope I'm explaining it adequately. Best, Joe

nononsense

kc5gxc,

"...can be mounted on almost any type of rifle and with the co-witnessing (applicable to many small calibre weapons) the iron sights are visible through the sight as a back-up."

From AR15.com:

User Info

UPDATED: 8/4/2006

What is BUIS anyway?

BUIS, or Back Up Iron Sights, come in many configurations. The purpose of a BUIS sytem is to give the shooter the ability to accurately aim the rifle if the primary optic fails.

What types are available?

Two types are available, flip up and fixed. It is possible to combine the two systems and use a flip up in the rear and a fixed FSB (front sight base) or vise versa.

What is co-witness?

A: Co-Witness is the ability of your irons to look through your optic (1x - not magnified) - so they both shoot on the same trajectory. There are two kinds - absolute (both the dot and irons are on the same plan), and offset (where the irons are usually in the lower 1/3 of the optics display). With co-witnessed sights you can verify the zero of the optic by looking through the irons (the dot should sit on top of the front sight). However, normally you look over the irons and just use the optic (trust me, you won't notice the iron sights); should the batteries fail your head comes down a fraction of an inch and you're using the iron sights (looking throught the now-dead optic).
(from the Maryland AR15 Shooters FAQ)

Best.

kc5gxc

Thanks for all the info, gents.....I had been wondering about that. I want to put a Ultimak rail on a mini 14 and they say the sight mounted on that will cowitness.....I may try to email them to get their version of exactly what they mean.
Thanks......Pete in MS