RDS: Co-Witness or Lower 1/3 Co-Witness... your thoughts?

[Renegade]

You don't need to use them together to be a co witness. The sight height for both your optic and irons are on the same plain, they are co witnessed. You don't need to adjust your head or cheek weld to use either.

MM

whatever

[Mysteryman]

whatever

Not trying to be a dick but it isn't a "whatever". Co witnessing or lower 1/3 co witnessing your irons has nothing to do with whether you run them up or not. Co witnessing is about where your iron sights line up with your optic(non magnified that is). Proper terminology is important for clear effective communication.

MM

[MadDog]

Not trying to be a dick but it isn't a "whatever". Co witnessing or lower 1/3 co witnessing your irons has nothing to do with whether you run them up or not. Co witnessing is about where your iron sights line up with your optic(non magnified that is). Proper terminology is important for clear effective communication.

MM

You are absolutely correct. With Absolute the BUIS will line up in the center of the optic's tube with the dot OFF. Lower 1/3 the BUIS will line up at the bottom third of the optic's tube with the dot OFF. When you turn the dot on it is a whole other animal as you can get the dot to sit on top of the front sight post regardless of which height mount you go with. The dot will float and still hit POA = POI. Many like the lower 1/3 because there is less of the front sight cluttering up the optic when looking dead center. I happen to be able to block out the front sight tower easily so I like an absolute co-witness as my optic will sit lower on the rail which gives my face a better cheek weld. With a 1/3 mount I am bordering on a chin weld.

[WatchTheWorldBern]

Can anyone with experience running lower 1/3 with front and rear flip ups explain why they choose that over absolute? Doesn't make sense to me (I understand lower 1/3 if you're stuck with a fixed gas block sight), but I've never done it.

[Barvan40]

The only time 1/3 or absolute really matters for me is when the red dot fails. At that point you are going to need your BUIS. When using my red dot I shoot both eyes open, but when using my sights I use my dominant eye only. With 1/3 I can see more of the area around the target through my RDS giving me better situational awareness. This is a big deal under dynamic and stressful conditions.

It would not do to have an innocent person unexpectedly step into the line of fire and get hurt because your view was limited by having a large part of the sight picture blocked by an absolute cowitness BUIS. With a greater part of the area around your target visible in 1/3 cowitness chances are you are more likely to see that person in time and hold your shot.

[sasquatchoslav]

I'm a huge fan of this approach and being an old fart raised on iron sights exclusively for probably 10 years b/f I started using glass I always like keeping them right 'at my side'. As far as 'weirdo' statuss goes I probably get asked 10x a year 'why do you shoot with your BUIS set popped up?'. Because I switch back and forth b/t scope and BUIS every time at the range. If my optics ever go down it's a seamless transition to BUIS. Got to do this last year when my batts went bye bye and didn't even flinch in the middle of my 30 round mag just kept on pinging.

[Mysteryman]

You are absolutely correct. With Absolute the BUIS will line up in the center of the optic's tube with the dot OFF. Lower 1/3 the BUIS will line up at the bottom third of the optic's tube with the dot OFF. When you turn the dot on it is a whole other animal as you can get the dot to sit on top of the front sight post regardless of which height mount you go with. The dot will float and still hit POA = POI. Many like the lower 1/3 because there is less of the front sight cluttering up the optic when looking dead center. I happen to be able to block out the front sight tower easily so I like an absolute co-witness as my optic will sit lower on the rail which gives my face a better cheek weld. With a 1/3 mount I am bordering on a chin weld.

The only time 1/3 or absolute really matters for me is when the red dot fails. At that point you are going to need your BUIS. When using my red dot I shoot both eyes open, but when using my sights I use my dominant eye only. With 1/3 I can see more of the area around the target through my RDS giving me better situational awareness. This is a big deal under dynamic and stressful conditions.

It would not do to have an innocent person unexpectedly step into the line of fire and get hurt because your view was limited by having a large part of the sight picture blocked by an absolute cowitness BUIS. With a greater part of the area around your target visible in 1/3 cowitness chances are you are more likely to see that person in time and hold your shot.

The FOV argument is utter nonsense. Whether you have a fixed front sight base or not it to makes no difference. The FOV when using a reddot sight(or an OEG for that matter) is exactly the same as what you see while looking at the computer screen. BOTH EYES OPEN means your brain is receiving as much visual stimuli as possible. Having binocular/stereoscopic vision allows us to look "through" the FSB and the reddot housing thanks to the unobstructed view of the non dominant/aiming eye. With both eyes open and your focus on the target, there is absolutely no loss of FOV.

The lower third co witness being less cluttered is also flawed. With your irons in the lower third, the gain in peripheral area when aiming with one eye only(again not ideal but is most often the case) around the front sight is gained ABOVE the sight more than BESIDE the sight by design. The widest point across a circle is called... The diameter, and it is found at the centre of the circle, where it perfectly bisects the shape. It is not found in the lower third. Having an absolute co witness puts the most free space directly opposite both sides of the front sight post. Why you would want or need more viewing area above the front sight post is beyond me. Furthermore, when using iron sights you are to focus on the front sight as the shot is taken, which means you shouldn't in theory ever see that innocent person step into view, so it's a moot point. If you aren't shooting then the rifle shouldn't be mounted as the iron sights offer no advantage for PID of the target or improved precision for the shot. Burying your head behind the irons and leaving it there only serves to diminish your situational awareness even more. Keeping both eyes open and scanning for targets can be accomplished with irons or optics, whether the rifle is mounted or not. Upon finding a target you can rough align the rifle with the target by mounting the rifle with both eyes open(if it isn't already mounted) and then close the non dominant eye to allow for a finite focus on the irons for the shot.

If we are talking about a defensive shoot or offensive shoot, there will be a lot going on, and tunnel vision and flattening of the cornea are some of those things. Neither of which help you remain alert and cognizant of your surroundings. I mention this because I find worrying about the FOV of your irons through your optic and the perceived advantages of the lower 1/3 cowitness over absolute cowitness to be pointless. What I see making more of a difference is the consistent cheek weld and thus sight picture offered by the absolute cowitness. Being able to practice your iron sight skills with the aid of your reddot is a cheap tool that pays dividends every time you use it. With most of us mounting our reddots with some form of QD mount, there is no need to fret over so called "cluttered FOV" as the optic comes off without delay or fuss. I know some will proclaim that there might be a time where you need to shoot NOW and you can't remove your optic. To that I say, **** it, make do with what you have and solve the problem. To plan for such near impossible events is akin to mental masturbation.

MM

[sidewaysil80]

I prefer absolute but will only use folding sights. Thus, they aren't obstructing anything.

[Leuthas]

The FOV argument is utter nonsense. Whether you have a fixed front sight base or not it to makes no difference. The FOV when using a reddot sight(or an OEG for that matter) is exactly the same as what you see while looking at the computer screen. BOTH EYES OPEN means your brain is receiving as much visual stimuli as possible. Having binocular/stereoscopic vision allows us to look "through" the FSB and the reddot housing thanks to the unobstructed view of the non dominant/aiming eye. With both eyes open and your focus on the target, there is absolutely no loss of FOV.

The lower third co witness being less cluttered is also flawed. With your irons in the lower third, the gain in peripheral area when aiming with one eye only(again not ideal but is most often the case) around the front sight is gained ABOVE the sight more than BESIDE the sight by design. The widest point across a circle is called... The diameter, and it is found at the centre of the circle, where it perfectly bisects the shape. It is not found in the lower third. Having an absolute co witness puts the most free space directly opposite both sides of the front sight post. Why you would want or need more viewing area above the front sight post is beyond me. Furthermore, when using iron sights you are to focus on the front sight as the shot is taken, which means you shouldn't in theory ever see that innocent person step into view, so it's a moot point. If you aren't shooting then the rifle shouldn't be mounted as the iron sights offer no advantage for PID of the target or improved precision for the shot. Burying your head behind the irons and leaving it there only serves to diminish your situational awareness even more. Keeping both eyes open and scanning for targets can be accomplished with irons or optics, whether the rifle is mounted or not. Upon finding a target you can rough align the rifle with the target by mounting the rifle with both eyes open(if it isn't already mounted) and then close the non dominant eye to allow for a finite focus on the irons for the shot.

If we are talking about a defensive shoot or offensive shoot, there will be a lot going on, and tunnel vision and flattening of the cornea are some of those things. Neither of which help you remain alert and cognizant of your surroundings. I mention this because I find worrying about the FOV of your irons through your optic and the perceived advantages of the lower 1/3 cowitness over absolute cowitness to be pointless. What I see making more of a difference is the consistent cheek weld and thus sight picture offered by the absolute cowitness. Being able to practice your iron sight skills with the aid of your reddot is a cheap tool that pays dividends every time you use it. With most of us mounting our reddots with some form of QD mount, there is no need to fret over so called "cluttered FOV" as the optic comes off without delay or fuss. I know some will proclaim that there might be a time where you need to shoot NOW and you can't remove your optic. To that I say, **** it, make do with what you have and solve the problem. To plan for such near impossible events is akin to mental masturbation.

MM

Nobody has made the claim to be shooting with one eye open, and forcing that factor into another's argument, in order to defeat it, isn't very clever.

You're actually making the assertion that a shooter cannot perceive a red dot housing within his view. I don't think that needs a rebuttal. Regardless, this tells me you have in your head the image of looking through an optic very close to the eyes and not one mounted forward on the receiver - so, limited experience.

A little condescension with a smattering of blatant practical ignorance.

Overall, I've had the impression that you find yourself well read on the subject but absolutely bereft of any practical experience on the matter whatsoever - and it doesn't make you seem intelligent.

[Mysteryman]

Nobody has made the claim to be shooting with one eye open, and forcing that factor into another's argument, in order to defeat it, isn't very clever.

Never said anyone made the claim, just telling you what I see frequently both at the range and from online discussions. People are often too stupid to read the f**king manual and use them incorrectly. Then proceed to talk sh*t about reddots when they haven't the faintest clue how they work or how they're to be used. I mention two eye open use because of this. Eliminating confusion on the discussion goes a long way to preventing the need to backtrack.

You're actually making the assertion that a shooter cannot perceive a red dot housing within his view. I don't think that needs a rebuttal. Regardless, this tells me you have in your head the image of looking through an optic very close to the eyes and not one mounted forward on the receiver - so, limited experience.

Thanks for guessing as to my experience and my usage of optics, but you would be wrong. I like my reddot on the far end of the receiver, not molesting my eye like a low dollar optic with near zero eye relief. I never said the optic housing was imperceptible, I'm saying that your view is unobstructed and unaffected by the ghosted image of the housing. Focus on the target, not the dot, and not the sight housing. It's really not that difficult.
A little condescension with a smattering of blatant practical ignorance.

Overall, I've had the impression that you find yourself well read on the subject but absolutely bereft of any practical experience on the matter whatsoever - and it doesn't make you seem intelligent.

In the bold.

MM