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AR15.COM
12/22/2024 5:29:33 PM EDT
Is anyone else running this mount? it is definitely taller than my factory holosun mount and will not co-witness with my  mbus 3s
12/25/2024 10:50:03 PM EDT
[#1]
If the mount is a lower 1/3rd witness, it means that the iron sights will be viewed thru the red dot sight below the red dot in the lower 1/3 of the red dot's view.

If one wishes the iron sights to co-witness with the red dot, a co-witness mount is required, not a 1/3rd lower mount.
12/26/2024 12:07:47 AM EDT
[#2]
Quote History
Originally Posted By Singlestack_Wonder:
If the mount is a lower 1/3rd witness, it means that the iron sights will be viewed thru the red dot sight below the red dot in the lower 1/3 of the red dot's view.

If one wishes the iron sights to co-witness with the red dot, a co-witness mount is required, not a 1/3rd lower mount.
View Quote


they are lower than 1/3 as in the base of the optic shrouds them. it is visibly taller than my other 1/3 mount.
12/28/2024 11:15:15 PM EDT
[#3]
Something doesn't sound right.

Are you sure they are not the AT 22 version (1.93" height)?
12/29/2024 10:33:21 AM EDT
[Last Edit: tallanm][Edited] [#4]
Quote History
Originally Posted By Singlestack_Wonder:
Something doesn't sound right.

Are you sure they are not the AT 22 version (1.93" height)?
View Quote


it measures about that high. is marked as at21. In contact with BCM.Attached File
Attached File
12/29/2024 7:47:40 PM EDT
[#5]
BCM will make it right if it is their problem.

Does the holosun rds you have have the same base to center dimension as an Aimpoint Micro (T1, T2, etc)?
12/30/2024 12:19:16 AM EDT
[#6]
…a holosun will sit higher than an aimpoint as they have a bit more height on the base of the optic.
12/31/2024 1:13:17 PM EDT
[#7]
Quote History
Originally Posted By Toddles:
a holosun will sit higher than an aimpoint as they have a bit more height on the base of the optic.
View Quote
There's a clue.
1/2/2025 3:13:16 PM EDT
[#8]
Quote History
Originally Posted By Singlestack_Wonder:
There's a clue.
View Quote


Yes, the bcm is more 1/6 than 1/3, previous mounts have worked with buis and holosun.
2/19/2025 10:48:01 PM EDT
[#9]
I used to have a 403r and they definitely are taller than a t2 from the base where it mounts to the optical centerline.

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