Rifle Scopes Co-witnessing front sight ?

[Cserv]

Was at the range today, and a couple spots down a couple guy's were trying to sight in a new AR. It had a flat top upper, with the A-2 front sight. He had a POS NcStar Reflex type sight on it and was having a hell of a time even getting on paper. So I go down to try and help them get sighted in. Told them to break it down, set the upper on their rest and my rear bags, and bore sight it. Just to try and get close. After getting him hitting paper, I hear the other guy tell him to always hold the reflex cross-hair on the front post. Is this the way it's done? I have never set up a rifle with an optic co-witnessing the front sight, so I don't know. In setting up this way, do you adjust your elev. with the irons and windage with the reflex? How is this done. Have no need for myself yet(I run a mini-14)but will one day have an AR platform, and am sure I'll see others struggling through the same at the range again. Thanks for any advise.
Eric
p.s. also advised the guy that the NcStar was not a very good piece of equipment, and he might think of upgrading ASAP. At least in my limited experience with the brand they are junk. Fell for it at a gun show several years ago. Mount and scope both junk!

 

[Jig Stick]

Re: Co-witnessing front sight ?

Cowitnessing was real big over at AR15.com not too long ago. A lot of guys seem to do it. Is it crucial....? Maybe. Maybe not.

 

[Cserv]

Re: Co-witnessing front sight ?

Seems to me like it would just complicate your sight picture. IDK?

 

[DP425]

Re: Co-witnessing front sight ?

Cowitness is the biggest load of horse-shit ever in the terms those guys are talking.

It is handy if you have lets say an aimpoint set up forward on your upper with a BUIS on the back- if the aimpoint goes down, you can flip up your rear sight and sight through your red-dot, centered up. In this method, assuming your irons are zeroed, and you have absolute co-witness, you can use your irons to get your red dot on paper by lining up EVERYTHING (looking through peep, front sight post centered, dot centered on it all. But that's a lot more difficult to adjust to than it sounds and bore-sighting would be much easier.

Otherwise, you should 100% ignore your front sight. The point of a red dot is NOT to replace a rear sight, it is to be THE (readnly) sight. Anyone that advocates co-witness does not have a very good understanding of how red-dot or holographic sights work and should really contact a couple reputable manufactures support departments.

 

[USACS]

Re: Co-witnessing front sight ?

Co-witness is a personal preference more than anything. In law enforcement and military usage, the concept is to have a backup in case your optic goes down. If the sight goes down, you don't have to remove it to utilize the sights. Co-witness will allow you to see your iron sights through the optical window or tube, depending on model; be it collimator sight, holographic weapon sight, or reflex sight. A "perfect" or "absolute" co-witness is basically where the red dot, chevron, or sight reticle sits directly on top of the front sight post within your sight plane.

I know lots of guys that run all their electronic sights with an iron sight co-witness. Almost all of them swear by the A2 front sight post and despise BUIS/flip-ups. Many also use solid rear sights that don't flip-up/down or move. I find this very distracting. I can understand keeping the front sight post, or a BUIS front sight post flipped-up, and I actually do consider that an acceptable option as you can aim using your front sight only and make accurate hits out to about 15yds. However, having the rear sight up constantly is just an annoyance to me.
I get lots of crap because I run BUIS down. I run an Aimpoint Micro T-1. Thing is, I've NEVER heard of a single account where a quality optic like an Aimpoint, EOTech or Trijicon have gone down in the middle of a firefight. The products are reliable enough to make this habit unnecessary. I understand that things "can happen", but if you know you're going into a major situation, you should be cognizant of your battery level, damage, adjustments, etc.
And to me honest, if the optic DOES go down, It will literally take me a less than 5 seconds to put up my sights and get back on target. It's about the same amount of time it would take to do a transition to my pistol.

 

[tt350z]

Re: Co-witnessing front sight ?

Well, in their defense, they are using a NcStar scope. So it's bound to break pretty soon

. That would place a premium on co-witnessing. The AR15.com view on cowitnessing is pretty much if you don't you're wrong.

I personally just run a 1-4x Meopta on mine. Keep in mind I use it for range and varmint hunting purposes so I won't be taking direct fire anytime soon to take the optic out.

Even if it goes down in a HD situation, the longest shot I can take in my home is 10 yards, so reactive shooting is much more important than taking time for a well placed shot.

 

[JSTARSZ]

Re: Co-witnessing front sight ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: USACS</div><div class="ubbcode-body"> However, having the rear sight up constantly is just an annoyance to me.

And to me honest, if the optic DOES go down, It will literally take me a less than 5 seconds to put up my sights and get back on target. It's about the same amount of time it would take to do a transition to my pistol. </div></div>
that is the way I do it too. The rear site is just something for my eye to focus on so I run with it down. I do practice the Aimpoint battery died scenario and use the sites for back-up.

 

[Sterling Shooter]

Re: Co-witnessing front sight ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body">Cowitness is the biggest load of horse-shit ever in the terms those guys are talking.

It is handy if you have lets say an aimpoint set up forward on your upper with a BUIS on the back- if the aimpoint goes down, you can flip up your rear sight and sight through your red-dot, centered up. In this method, assuming your irons are zeroed, and you have absolute co-witness, you can use your irons to get your red dot on paper by lining up EVERYTHING (looking through peep, front sight post centered, dot centered on it all. But that's a lot more difficult to adjust to than it sounds and bore-sighting would be much easier.

Otherwise, you should 100% ignore your front sight. The point of a red dot is NOT to replace a rear sight, it is to be THE (readnly) sight. Anyone that advocates co-witness does not have a very good understanding of how red-dot or holographic sights work and should really contact a couple reputable manufactures support departments.</div></div>

+1, most folks who buy dot sights don't even know why they should want one. It's just a monkey see monkey do thing. They perceive for what ever reason a soldier has an Aimpoint, that's good enough for them too, even when it is not understood what benefit the dot sight provides. What I'm alluding to is there appears to be quite a few monkeys out there with AR's.

 

[PLeighton]

Re: Co-witnessing front sight ?

Another reason to co-witness is to be able to flip up the rear BUIS and put your nose to the charging handle to make a more precise shot at distance.
If my sight picture is correct in the irons, then I know that the tip of the chevron is going to be my absolute point of aim.

Sure, these optics are "parallax free", but it is more like "parallax tolerant".
Try it out...
Get on your gun, get a good sight picture using your optics, then move your head around.
The dot / chevron moves around ever so slightly doesn't it???

YMMV...

By the way, tell your friend to smash that NC Star with a hammer ASAP.
He'll spend more money on ammo chasing the reticle on that thing than he would on a quality optic.

 

[DP425]

Re: Co-witnessing front sight ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dr. Phil</div><div class="ubbcode-body">Another reason to co-witness is to be able to flip up the rear BUIS and put your nose to the charging handle to make a more precise shot at distance.
If my sight picture is correct in the irons, then I know that the tip of the chevron is going to be my absolute point of aim.

Sure, these optics are "parallax free", but it is more like "parallax tolerant".
Try it out...
Get on your gun, get a good sight picture using your optics, then move your head around.
The dot / chevron moves around ever so slightly doesn't it???

YMMV...

By the way, tell your friend to smash that NC Star with a hammer ASAP.
He'll spend more money on ammo chasing the reticle on that thing than he would on a quality optic. </div></div>

They are supposed to move around- beyond 25m, at a man size target, an aimpoint will hit target if the dot is center, all the way left in your FOV, all the way bottom or any combination.

I'm not going to sit here and argue that co-witness does nothing to improve accuracy, or that it even has the potential to decrease accuracy... I don't need to... the manufactures make this argument for me... as does the military (and I'm not talking about the half-wit idiots who pick it up and assume- I'm talking about those who read the manual and have been to CQM course).

I think I'm going to set-up two sets of iron sights on my AR, and run a CompM2 in conjunction with an aimpoint micro... Should DEFF improve my accuracy; I'll be lining up FOUR sights. NO WAY I can miss then!!

I agree with you on smashing the NCStar

 

[PLeighton]

Re: Co-witnessing front sight ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body">
They are supposed to move around- beyond 25m, at a man size target, an aimpoint will hit target if the dot is center, all the way left in your FOV, all the way bottom or any combination.

I'm not going to sit here and argue that co-witness does nothing to improve accuracy, or that it even has the potential to decrease accuracy... I don't need to... the manufactures make this argument for me... as does the military (and I'm not talking about the half-wit idiots who pick it up and assume- I'm talking about those who read the manual and have been to CQM course).

I think I'm going to set-up two sets of iron sights on my AR, and run a CompM2 in conjunction with an aimpoint micro... Should DEFF improve my accuracy; I'll be lining up FOUR sights. NO WAY I can miss then!!

I agree with you on smashing the NCStar </div></div>
I think you may have misunderstood me a bit.
In fact, you reinforced the point I was trying to make.

Specifically that the optic should be the primary aiming device and the BUIS only utilized when precision shots are required.
If you zero with the BUIS and adjust the optic to match, there won't be enough difference while shooting with the BUIS down to matter.
Conversely, if you zero with the optic and then transition to the BUIS, you will end up with two separate sight pictures.
(Well that is about as clear as mud.)

Bottom line, the BUIS have a secondary use as an additional tool to aid in precision fire if used in the prescribed manner.
Run with the rear BUIS down and only flip them up if you need to make a crucial shot from a supported position.

 

[DP425]

Re: Co-witnessing front sight ?

Alright, I think I get what you're sayin! Sorry about the misunderstanding!

 

[USACS]

Re: Co-witnessing front sight ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JSTARSZ</div><div class="ubbcode-body">
that is the way I do it too. The rear site is just something for my eye to focus on so I run with it down. <span style="font-weight: bold">I do practice the Aimpoint battery died scenario and use the sites for back-up.</span></div></div>
That's always a good practice, for just-in-case when the excrement hits the oscillating wind generator.

 

[buggsb]

Re: Co-witnessing front sight ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body">Cowitness is the biggest load of horse-shit ever in the terms those guys are talking.

It is handy if you have lets say an aimpoint set up forward on your upper with a BUIS on the back- if the aimpoint goes down, you can flip up your rear sight and sight through your red-dot, centered up. In this method, assuming your irons are zeroed, and you have absolute co-witness, you can use your irons to get your red dot on paper by lining up EVERYTHING (looking through peep, front sight post centered, dot centered on it all. But that's a lot more difficult to adjust to than it sounds and bore-sighting would be much easier.

Otherwise, you should 100% ignore your front sight. The point of a red dot is NOT to replace a rear sight, it is to be THE (readnly) sight. Anyone that advocates co-witness does not have a very good understanding of how red-dot or holographic sights work and should really contact a couple reputable manufactures support departments. </div></div>

What he said...

BUIS is just that...backup if your optic goes down. All these people tryint to "cowitness" have no clue how to run a dot optic.

 

[carbinero]

Re: Co-witnessing front sight ?

I like co-witness. Once you get used to it, it's fast for target acquisition. If you have a fold down rear BUIS (Troy for metal, or Magpul for less $), you can put it down if you want. Regardless, just sight it in with the irons, then adjust the dot just above the front post. Easy.

 

[M25BeastShooter]

Re: Co-witnessing front sight ?

Co-witnessing the iron sights and the red dot or holographic sights for combat/LEO is a quick check of your red dot as iron sights seldom get bumped so hard as to knock them off. I flip up the back up rear getg a good check weld/sight picture and if the red dot is setting on top of the front sight then the red dot is still zeroed. While this might not be the most precise zeroing method it does provide a method of checking the red dot prior ro going through the door.

 

[Cserv]

Re: Co-witnessing front sight ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body">Cowitness is the biggest load of horse-shit ever in the terms those guys are talking.

It is handy if you have lets say an aimpoint set up forward on your upper with a BUIS on the back- if the aimpoint goes down, you can flip up your rear sight and sight through your red-dot, centered up. In this method, assuming your irons are zeroed, and you have absolute co-witness, you can use your irons to get your red dot on paper by lining up EVERYTHING (looking through peep, front sight post centered, dot centered on it all. But that's a lot more difficult to adjust to than it sounds and bore-sighting would be much easier.

Otherwise, you should 100% ignore your front sight. The point of a red dot is NOT to replace a rear sight, it is to be THE (readnly) sight. Anyone that advocates co-witness does not have a very good understanding of how red-dot or holographic sights work and should really contact a couple reputable manufactures support departments.</div></div>
After his buddy abandoned him, to go to the pistol range while I was trying to get him on target, I told him to disregard his friends advice, and just use the optic. Myself not being familiar with the whole co-witness set-up. Then told him he needed irons for the rear, because what he had was going to break and waste alot of ammo, while causing him much frustration.
Thanks for all the replies, helped clarify for me. And will help out the next time I see a new shooter struggling at the range.
Eric

 

[rjroberts]

Re: Co-witnessing front sight ?

That's why I don't even own a red-dot sight. Yes, my scope has a red dot in a circle but that's for when I use the scope. Otherwise, it's irons only. I put a Meprolight in the front and look at that "dot". A half-way decent cheek-weld puts me on the rear sight so I'm sure it's lined up: all I do is look at the green dot.

I would have minded if my scope "co-witnessed" but it's not an objective. I have the scope higher because I prefer fixed irons to the flippers, and the fat eyepiece won't clear. If you do co-witness, you'll find that the front sight disappears around 3 or 4x.