No this is not another lame cowitness question and I searched keyword back 18 months this has not been discussesd. CHECKO just posted an awesome picture of his cowitness looking through his rear sight to show his 1/3 in the AR pics section

 

I completely understand the point of cowitness my question is I'm presuming most guys leave rear sight down when using optic as CHECKO stated. But then you can see in the pic when rear sight is up the red dot is not in the middle of the picture, I assume because of the 1/3 choice. So then this has to mean that his cheek/eye weld is different when using the optic vs both irons. Is this okay?

 

I'm really glad he posted that pix because If all the millions of pics of cowitness on the web it is rarely through the rear sight. It's mostly "optic vs front sight". So if you zero your irons. Then flip them down and zero your red, you run the "risk" that your irons AND the red dot are in the bottom 1/3 when looking through all 3. Is that normal?

 

I guess in real life if your optic failed you would rip it off and use irons and then there is no 1/3 thing but I just thought it was weird seeing both irons and red dot in bottom 1/3 simultaneously

 

Thank you CHECKO for the picture. The genesis of this question is I'm pondering my first build and and grappling with the FSB being permanent versus flip up for both

 

So the question: zero irons is separate from zero optic and don't care ever about looking through all 3?

Unless of course your preference is to have the red dot in the bottom third all along. Then the above is perfectly normal and just personal preference

Hey Barms... can you provide a link back to the picture/thread that you are referring to? Thanks.

Nevermind. Got it.

 

http://njgunforums.com/forum/index.php/topic/10555-ar-pics-lets-seeum/?p=771040

Yes, if I transition to the irons in a lower 1/3 config my cheekweld changes but it is very small. I run this way:

 

Small amount of realestate (aimpoint T1 Micro) true cowitt with rear iron folded.

More realestate (aimpoint m3/m4) lower 1/3 cowitt with irons always up.

I'll try to answer the best I can. Let me know if there is anything I miss.

 

I like the lower 1/3 because there is less front sight post in my field of view when looking through my optic(tube, window, what have you). The beauty of the red dot/holo is that you don't need to have precise cheek weld to know where you're hitting like with Irons. If you lift your head up a little the dot will be in the middle with minimal change in cheekweld as Shane said. The dot will tell you point of impact (assuming its zeroed) no mattrr the viewing angle. You would NOT have to rip off your optic if it fails because you can still look right through the red dot.

 

All in all, when you co witness and focus on the TARGET everything else seems to disappear.

What I did was zero my irons, then place my dot on top of the fsp while looking through the rear sight. Easy zero. Then verify at the range.

 

 

I use a lower 1/3 co-witness on all of my RDS equipped guns. I prefer a standard fixed front sight assembly with a folding rear BUIS and I leave the rear sight down unless I need it. Subjectvely, I also prefer the less cluttered sight picture and the slightly more "heads up" position the taller optic mount on a lower 1/3 co-witness affords me. It is a little less fatiguing and feels more natural.

 

It does require a subtle shift (it is so minimal I hesitate to label it an actual "movement") of the head position/cheek weld to switch from optic to irons, but since it is folded I will likely be moving my head a lot more just to deploy the sight. At its best, it is really no different than the the slight changes you make while acquiring your next target while driving the gun and engaging multiple threats, and at its worst the movement you would need to bring the rifle from a low ready (45 deg muzzle depressed) to being aimed in. It is quick and intuitive.

 

Additionally, inside 10 yards - 15 yards with practice - barring a high precision/low percentage shot you don't even need to flip that BUIS up. You can use the actual tube/box (Aimpoint/EoTech) of the optic as a ghost ring and be assured of decent center mass hits placed rapidly until you can get to a position of advantage where you can take the 1/4 second to flip the BUIS up and continue the fight.

 

The only time you will need to remove the optic before deploying BUIS is if you have an ACOG or other magnified optic or a variable power/magnifier that actually covers the BUIS preventing it from being deployed.

 

All in all, when you co witness and focus on the TARGET everything else seems to disappear.

I can't stress this statement enough. With just a little time behind a lower 1/3 co-witnessed RDS and with proper initial training, this becomes true. You don't notice the front sight any longer because you don't have to worry about moving the front sight out of the way to see your target with the red dot superimposed on it.

 

ETA: Oh, and I typically do the opposite of Checko. I zero my RDS then I set my irons to that and confirm my zero by shooting a 10 round group. However, if I was putting an RDS on a carbine with previously zeroed iron sights, I would co-witness them and adjust the RDS to meet the irons, then shoot a confirmation group.

ETA: Oh, and I typically do the opposite of Checko. I zero my RDS then I set my irons to that and confirm my zero by shooting a 10 round group. However, if I was putting an RDS on a carbine with previously zeroed iron sights, I would co-witness them and adjust the RDS to meet the irons, then shoot a confirmation group.

That's what I had. I switched my optics out and had my zeroed irons.

 

One other note for using non magnified optics: keep both eyes open!

Okay I'm clear on this

 

I just wanted make sure I wasn't crazy here when i saw the red dot much lower when looking through the rear sight. Again, I totally understand the 1/3 idea on the FRONT SIGHT. Most pictures have red dot bullseye middle and front sight at 1/3. But when I saw yours looking through REAR and the red dot was now not in the middle anymore thats when I had I ask about moving your head between transitions

Yup the red dot will move around in the window with your view angle, but always have the are point of impact