Co-Witness


Firearm & Gun Forum - FireArmsTalk.com > Long Guns > Auto & Semi-Auto Discussion > AR-15 Discussion > Co-Witness

Reply
 
LinkBack Thread Tools Display Modes
Old 04-02-2009, 10:27 PM   #1
Feedback Score: 0 reviews
 
Join Date: Apr 2009
Posts: 3
Liked 1 Times on 1 Posts

Default Co-Witness

Does anyone one know what the "elevation" (distance form top of rail to bottom of circumference) and "line-of-sight" (distance form top of rail to dead center) heights are for "absolute co-witness" and "co-witness" on a 30mm sight/scope?

by my calculations:

"Absolute Co-Witness"
The rear sights "line-of-sight" is 35mm high.
The center of the 30mm circumference is 15mm.
15mm - 35mm = 20 elevation

"Lower 1/3 "Co-Witness"
Would add 3-4mm to the 20mm above to be able to see it go over the rear aperture.
So its elevation would be 23-24mm

Does that look right? For some reason everybody hides these numbers on their claims of "co-witness"

Thanks!



__________________
DiveFlyFun is offline  
 
Reply With Quote

Join FirearmsTalk.com Today - It's Free!

Are you a firearms enthusiast? Then we hope you will join the community. You will gain access to post, create threads, private message, upload images, join groups and more.

Firearms Talk is owned and operated by fellow firearms enthusiasts. We strive to offer a non-commercial community to learn and share information.

Join FirearmsTalk.com Today! - Click Here


Old 04-03-2009, 01:30 AM   #2
Feedback Score: 0 reviews
 
Join Date: Feb 2009
Posts: 202
Liked 23 Times on 19 Posts
Likes Given: 2

Default

ok you lost me.



__________________
crockett007 is offline  
 
Reply With Quote
Old 04-03-2009, 01:53 AM   #3
Feedback Score: 0 reviews
 
RL357Mag's Avatar
 
Join Date: Apr 2008
Location: Albany,New York
Posts: 3,251
Liked 4 Times on 4 Posts

Default

Ditto! What kind of gun are you talking about, what kind of optic are you talking about?

If you are discussing co-witnessing of BUIS with a scope, there is no concern, since the focal distance of the scope will not allow the front sight to come into focus or obscure your sight picture while looking through the scope. If you are talking about a rail mounted Holosight or similar optical device mounted in line with BUIS, the optical axis or "centerline" of the lens must be higher than an imaginary line extending from the top of the front sight to the top of the rear sight. But without knowing what type of gun, sights, or optical sight you are referrencing, any advice is impossible.

__________________
Guns Have Only Two Enemies-Rust and Politicians
"The United States Constitution (c) 1791 - All Rights Reserved"
If Guns Kill, Do Pencils Mis-spell Words?
Pain is Weakness Leaving the Body - USMC
"Qui desiderat pacem, praeparet bellum"
RL357Mag is offline  
 
Reply With Quote
Old 04-03-2009, 03:23 AM   #4
Feedback Score: 0 reviews
 
Join Date: Apr 2009
Posts: 3
Liked 1 Times on 1 Posts

Default

Sorry, my bad....An AR-15 Bushmaster Patrolman (M4A3) with a 30mm red dot.

__________________
DiveFlyFun is offline  
 
Reply With Quote
Old 04-04-2009, 12:43 AM   #5
Feedback Score: 0 reviews
 
RL357Mag's Avatar
 
Join Date: Apr 2008
Location: Albany,New York
Posts: 3,251
Liked 4 Times on 4 Posts

Default

You should have no problem with co-witnessing to a 30mm red dot as long as the center axis of the red dot is slightly higher than the front sight elevation.



__________________
Guns Have Only Two Enemies-Rust and Politicians
"The United States Constitution (c) 1791 - All Rights Reserved"
If Guns Kill, Do Pencils Mis-spell Words?
Pain is Weakness Leaving the Body - USMC
"Qui desiderat pacem, praeparet bellum"
RL357Mag is offline  
 
Reply With Quote
Reply

Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Firearms Forum Replies Last Post
EAA Witness---any good ? ladyM Semi-Auto Handguns 39 05-31-2013 12:57 PM
Aimpoint mount to get absolute co-witness? truevil1313 Firearm Accessories & Gear 13 12-05-2009 11:45 AM
EAA Witness? Smith .357? Gojubrian General Handgun Discussion 13 09-03-2009 03:14 AM