Sights/optics question

corpulent · Dec 7, 2010

Hi, I'm new to rifles and optics so...roll your eyes, forgive me, and lend some advice.

I just bought a red dot, paired with the stock iron sights on my 15-22. When cowitnessing, are both the front and rear irons used? It seems to obscure the POV so much with the rear on/up that it makes more sense to have the red dot and the front sight only. Is that the "proper" way or is there something inherently wrong with that?

For example, speaking from a comfort/ease of use perspective, my setup would have the red dot, fixed front, and flip-up rear (which would be folded down while using the dot).

Also, with mounted optics/sights/etc., they seem to be easily attached and removed. Is it common practice to swap stuff on and off or does that totally foul up calibrations and such? The mounts seem to "true" themselves on the rail well.

Thanks

grimreaper21 · Dec 7, 2010

If you can't use both the irons it isn't a real cowitness. The front sight won't help you without the rear sight. If you don't wanna use both I just would use the red dot only and get both folding irons.

Rustpot · Dec 7, 2010

I've posted these pictures in a few other spots, but they can help here too.

When using the iron sights you're looking through the body of the red dot (tube or reflex glass). The initial zero is done by lining up the front and rear sights as you would normally use them and putting the dot on the tip of the front sight. In this picture you can see the sights clearly through the tube body, but my dot is turned off. This particular cowitness is called "lower 1/3" since the irons are slightly below center.

When using the dot you have two options. You can look over the iron sights, which puts your dot higher on the glass. With a higher mount there's obviously more room to do this, which is an advantage of the "lower 1/3" setup.

Option 2 is to remove or fold the rear sight out of the way. The front sight would then be ignored as you use the dot.

And the advantage to having two flip sights is being able to fold the front down as well to have very little blocking your complete view of the target and its immediate surroundings.

If you're shooting with just the dot and want to remove the fixed sights you can do that. If you have them with you at the range and your dot stop working for whatever reason you can most likely put the sights back on and still be very close to zero. The stock rear sight has easy to use adjustment wheels, so even if you need to make a few clicks to realign POA and POI you're all set.

ChattanoogaPhil · Dec 7, 2010

If the question is: Do I need to look through the rear sight aperture to use a red dot, the answer is no.

Try this--- Zero your iron sights, then while looking through your iron sights adjust the red dot to line up with the tip of the front sight post. Your red dot is now zeroed with your sights. keep the rifle on target and still, and lift your eye above the rear sight aperture. You'll notice that the red dot remains on target even though you are not looking through the rear sight aperture.

Don't get hung up on the term co-witness.

CrazyFingers · Dec 7, 2010

Also keep in mind that you might need a riser to put your red dot in line with your iron sights, or just to make it comfortable to use the red dot.
Something like this:

Leapers UTG Deluxe Medium Profile Picatinny-Style Riser Mount AR-15 Flattop Matte - MidwayUSA

ChattanoogaPhil · Dec 7, 2010

CrazyFingers said:
Also keep in mind that you might need a riser to put your red dot in line with your iron sights

That's an excellent point. I have seen folks attempt to use red dots with integrated mounts that are too low.

Incredible Me · Dec 7, 2010

Will i need a riser with the combo of an 522 and Mbus flip sights?

corpulent · Dec 7, 2010

Thanks for the info. I've got a 1/3 cowitness w/ my high cant mount PA M3. Looking through the irons gives me a nice sight picture (dot, too), but when I slightly raise my head to favor the dot, the rear sight ends up cluttering my view more than I like. The top of the rear aperture ring sets right where the dot is, and makes everything a little hazy. So, I prefer to remove the rear if I'm going dot-only. Leaving the front on gives me a little perspective, a la COD: Black Ops. I guess I was just wondering if I was making some rookie mistake.

On that note, anyone know of a reasonable rear flip-up that isn't as obtrusive as the magpuls (i.e. without the knobs and "wings" so high). If there was just a flip up ring aperture or something like what MATECH offers, but on a budget. . .

Rust, why would you shoot Datsyuk? He's the perennial Lady Byng winner.

ChattanoogaPhil · Dec 7, 2010

Incredible Me said:
Thanks for the info.
I also guess that replica 522's are the same height as the original eotechs.

I thought you were talking about a Sig522...

EOTech and clones don't need risers.

Rustpot · Dec 7, 2010

corpulent said:
On that note, anyone know of a reasonable rear flip-up that isn't as obtrusive as the magpuls (i.e. without the knobs and "wings" so high). If there was just a flip up ring aperture or something like what MATECH offers, but on a budget. . .

Rust, why would you shoot Datsyuk? He's the perennial Lady Byng winner.

CA Sniper Rear Flip Sight by: Classic Army - Airsoft GI - Welcome to
Something like that might be what you're looking for.

And Datsyuk was conveniently on the dresser when I was taking pictures. Good reduced size target for dry fire and target transition at home too.

corpulent · Dec 7, 2010

So, again, forgive my noobishness if I'm blowing anyone's mind with the absurdity of my questions.

Does anyone make a rear buis with an open circle design? Say, something like the Troy-style FRONT, but smaller, adjustable, and missing the post of course. It would seem like the typical round rear aperture wouldn't suffer from a tiny arc missing from it's top edge.

I guess it's all moot if the overall message is that the irons and the dot DON'T get used simultaneously.

The Gen 2 MBUS and the N.A.W.S. might be just what I'm after. Wonder when they come out.

scanner · Dec 9, 2010

This link breaks it down "Barney Style"

Links to other forums aren't allowed. Phil

scootle · Dec 9, 2010

Something I learned is that the so-called lower-1/3 co-witness described in the pictures at the beginning of this thread by Rustpot (sometimes called "SOCOM" height) is designed to allow you to run a RDS or other reflex sight with fixed irons front/rear. Folding irons are not required with this setup since, obviously, you can view the RDS above the bulk of the fixed irons if you choose.

In most cases, though, people will put at least a folding rear iron in place to unclutter their view. Very often, the front sight post on a full-sized AR is a fixed post design that is not removable from the FSB, so it remains in place.

Flat-top AR designs with a low-profile gas block, however, can run an "absolute co-witness" setup (think of the lower-1/3 setup, but with the irons and RDS all dead center) which doesn't require a high riser but prefers folding irons front and rear to not block most of the optic sight picture.

Our 15-22s are complete flat-top designs, and we are not encumbered with a fixed FSB, so you can run either setup if you desire.

Good luck!

PS The thread in scanner's post just above this one is an excellent explanation of all of this. Hopefully the mods won't remove that link. If it is removed, at least here are the accompanying images that might be very helpful to understanding the terms.

Sights/optics question

corpulent

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