Aimpoint/BUIS co-witnessing Questions

MSchaefer223 · February 8, 2008, 03:30 AM

Hey Guys,

I have a sort of lengthy question and all parts need to be answered. I have a Rock River M4 flat top carbine. I have a Yankee Hill folding front sight tower model # 9394. I am planning to put on an A.R.M.S. folding rear sight model #40L or # 40L-P. I am also planning to mount an Aimpoint Comp ML3 red dot in an A.R.M.S. throw lever ring model # 22M68, with a cantilever spacer. I need to know if the front and rear sights I have selected will accurately work together. I need to know if this mount/spacer combo will make the scope and BUIS co-witness in the center of the scope or the lower 1/3. From the pictures I have seen, it should place it in the lower 1/3, but I am not sure. I have also looked into LaRue cantilever mounts also, but I don’t know if it will co-witness with my iron sights properly. Any relative worthwhile insights into this matter will be extremely appreciated.

AK103K · February 8, 2008, 04:42 PM

I think most of the Aimpoint mounts are built to cowitness with more or less basic BUIS on AR15's. I believe the BUIS are made to be the same height at the standard iron sights.

All the Aimpoint mounts I've used (Larue, ARMS, and GG&G) seem to have been at the correct height when mounted on a flat top Armalite.

I have GG&G BUIS's on one of my rifles, and use a GG&G cantilever Aimpoint mount with them. They cowitness perfectly. My Larue and my ARMS mounts seem to have had too.

This is my Armalite with the GG&G sights on it.

February 8, 2008, 03:30 AM	#1
MSchaefer223 Junior Member Join Date: February 4, 2008 Posts: 3	Aimpoint/BUIS co-witnessing Questions Hey Guys, I have a sort of lengthy question and all parts need to be answered. I have a Rock River M4 flat top carbine. I have a Yankee Hill folding front sight tower model # 9394. I am planning to put on an A.R.M.S. folding rear sight model #40L or # 40L-P. I am also planning to mount an Aimpoint Comp ML3 red dot in an A.R.M.S. throw lever ring model # 22M68, with a cantilever spacer. I need to know if the front and rear sights I have selected will accurately work together. I need to know if this mount/spacer combo will make the scope and BUIS co-witness in the center of the scope or the lower 1/3. From the pictures I have seen, it should place it in the lower 1/3, but I am not sure. I have also looked into LaRue cantilever mounts also, but I don’t know if it will co-witness with my iron sights properly. Any relative worthwhile insights into this matter will be extremely appreciated.

February 8, 2008, 04:42 PM	#2
AK103K Senior Member Join Date: May 1, 2001 Posts: 10,223	I think most of the Aimpoint mounts are built to cowitness with more or less basic BUIS on AR15's. I believe the BUIS are made to be the same height at the standard iron sights. All the Aimpoint mounts I've used (Larue, ARMS, and GG&G) seem to have been at the correct height when mounted on a flat top Armalite. I have GG&G BUIS's on one of my rifles, and use a GG&G cantilever Aimpoint mount with them. They cowitness perfectly. My Larue and my ARMS mounts seem to have had too. This is my Armalite with the GG&G sights on it.