Why co witness?

[bharrison913]

I am kinda of newbie so can somebody explain what the advantages to be had when you co witness a red dot with sights I have the flip up front and rear so why not just leave them down thanks

[Rustpot]

If the red dot battery dies you can flip the backup sights up and continue shooting by looking through the body of the optic. If the optic wasn't in a cowitness setup you'd be forced to remove it and risk losing it once it's off the rifle, or dropping and damaging it, or losing zero for when you put it back on.

You can also have the iron sights zeroed for a different range, allowing you to use them to take a long shot that you'd otherwise be guessing how much hold to apply to the dot.

Whether your iron sights fold when not in use or are fixed cowitnessing the optic is an option most people like to do.

[chuck s]

Co-witness of the sights preserves the trajectory reference the line of sight between the muzzle and the target.

This is important in battlesight riflery. The 200 meter Improved Battlesight Zero (for the M4 Carbine) has a maximum of 2" difference from line of sight from just beyond the muzzle to about 220 meters and consequently requires no hold-over or -under in that range band. This only works with the iron sights or a dot positioned the same 2.6" over bore as the iron sights. Co-witnessed. At a different height above bore there will be differences between line of sight and trajectory that may need hold-over or -under at mid ranges.

In a slower velocity .22LR plinker co-witnessing may be more important as the trajectory is much higher and different heights above bore will produce much different mid-range trajectories vs line of sight.

No need to flip anything with properly positioned sights. Other than the need to flip the switch and covers open.

Here's an inexpensive dot sight co-witnessed. Maximum distance from the eye aids dot pickup and target transition.



And the M68 COO on my (very) old handled M4 Carbine and Aimpoint clone of the M&P-15-22 in the same position.



My M&P15-22 is my "3¢/round" trigger-trainer for my "30¢/round" carbine so both are set up the same way. Including co-witnessing the dot with the iron sights.

-- Chuck

[Nachtjager]

this is from an article that was posted a few pages back
Red Dot Sights / Reflex Sights & Holosights Explained

Co witnessing

It's often difficult to grasp the true simplicity of a new concept, so we make it complicated as a way of justifying our misunderstanding. So it is sometimes with co witnessing. The term means only one thing-- The ability to use either the optical sight or the iron sights, by changing almost nothing other than your attention. You are able to use the iron sights by looking through the lower portion of the electronic sight's viewing area. It does not mean that the iron sights and electronic reticle are used at the same time. Co witnessing simply gives you a redundant sighting system in case one of them fails, or you forget to switch on the electronic sight.
We occasionally have people tell us things like, "I finally got my dot to co witness about a quarter inch above the iron sights..." Again-- Nonsensical. If your electronic sight is zeroed for the same distance and wind as your iron sights, and you line up your iron sights while your electronic sight is turned on, you will see the electronic reticle aligned with the top of the front iron sight post. When using the electronic sight, you would typically look just over the top of the iron sights, such that the electronic sighting reticle appears to float above the iron sights. Again, the apparent position of the electronic reticle within the sighting window is of no consequence and it depends on the position of your eye. Once zeroed, the reflex dot can be at the very bottom, the extreme left, right, or top of the viewing area and it still represents your proper aiming point

My own point of view is that if you are using an optic that requires a battery then you should be carrying an extra battery with you. Most likely when you are using the MP15-22 it will not be in a combat situation, you will either be at the range, out plinking or varmit shooting so carrying an extra battery should be pretty easy.

If you are using a scope then there is no need to co-witness at all and no need to have your other sights cluttering up your rail, it is highly unlikely that you will be in such an emergency situation that you would have to use the iron sights. Once again I am guessing you are not using your rifle in combat but merely target shooting, plinking or varmit hunting and if for some reason your scope is knocked out of true then you need to resight anyway so might as well do it then.

I have been using scopes for over 30 years when big game hunting and never have I had the need to co-witness with iron sites or the need to back up the scope with another sighting system.

If you are at the range, plinking or varmit hunting I cannot imagine such a dire situation occuring where you would need to back up your primary sighting system and you should know enough to carry a spare battery and to be careful not to bang your scope around anyway. Afterall this is just a .22lr and it is not a rifle we would be using in emergency or combat situations so if you have a problem with your primary sighting system just fix it. There is no need for two or three sighting systems on a .22lr

I have a quick release scope and a quick release reflex sight and can easily switch between the two, my iron sights have been put away in a box somewhere and I have never had a situation where I needed to use them because the scope was knocked out of true or the reflex sight's battery did not work but there probably are those out there who may have been in a situation where they had to have another back up system

[safearm]

I carried a M4 with Aimpoint in combat in Iraq. We carried a lot of stuff with us, including extra batteries. In the heat of real battle, when real bad guys are shooting at you, it's a whole lot easier to flip up you BUIS and continue to engage, rather than change batteries.
We also marked the rear reticle of our Aimpoints with a magic marker dot. In daylight, you didn't need to turn it on, just use the back dot.
If you're at the range or shooting at targets that aren't shooting back, you can do away with iron sights and swap batteries.

[Rustpot]

Originally Posted by safearm

I carried a M4 with Aimpoint in combat in Iraq. We carried a lot of stuff with us, including extra batteries. In the heat of real battle, when real bad guys are shooting at you, it's a whole lot easier to flip up you BUIS and continue to engage, rather than change batteries.
We also marked the rear reticle of our Aimpoints with a magic marker dot. In daylight, you didn't need to turn it on, just use the back dot.
If you're at the range or shooting at targets that aren't shooting back, you can do away with iron sights and swap batteries.

How often did your Aimpoint run out of juice? With a 10,000 average life one would think you could leave it on and change the battery every 6 months and be golden.

[VooDuuChild]

Originally Posted by Nachtjager

this is from an article that was posted a few pages back
Red Dot Sights / Reflex Sights & Holosights Explained

Co witnessing

It's often difficult to grasp the true simplicity of a new concept, so we make it complicated as a way of justifying our misunderstanding. So it is sometimes with co witnessing. The term means only one thing-- The ability to use either the optical sight or the iron sights, by changing almost nothing other than your attention. You are able to use the iron sights by looking through the lower portion of the electronic sight's viewing area. It does not mean that the iron sights and electronic reticle are used at the same time. Co witnessing simply gives you a redundant sighting system in case one of them fails, or you forget to switch on the electronic sight.
We occasionally have people tell us things like, "I finally got my dot to co witness about a quarter inch above the iron sights..." Again-- Nonsensical. If your electronic sight is zeroed for the same distance and wind as your iron sights, and you line up your iron sights while your electronic sight is turned on, you will see the electronic reticle aligned with the top of the front iron sight post. When using the electronic sight, you would typically look just over the top of the iron sights, such that the electronic sighting reticle appears to float above the iron sights. Again, the apparent position of the electronic reticle within the sighting window is of no consequence and it depends on the position of your eye. Once zeroed, the reflex dot can be at the very bottom, the extreme left, right, or top of the viewing area and it still represents your proper aiming point

My own point of view is that if you are using an optic that requires a battery then you should be carrying an extra battery with you. Most likely when you are using the MP15-22 it will not be in a combat situation, you will either be at the range, out plinking or varmit shooting so carrying an extra battery should be pretty easy.

If you are using a scope then there is no need to co-witness at all and no need to have your other sights cluttering up your rail, it is highly unlikely that you will be in such an emergency situation that you would have to use the iron sights. Once again I am guessing you are not using your rifle in combat but merely target shooting, plinking or varmit hunting and if for some reason your scope is knocked out of true then you need to resight anyway so might as well do it then.

I have been using scopes for over 30 years when big game hunting and never have I had the need to co-witness with iron sites or the need to back up the scope with another sighting system.

If you are at the range, plinking or varmit hunting I cannot imagine such a dire situation occuring where you would need to back up your primary sighting system and you should know enough to carry a spare battery and to be careful not to bang your scope around anyway. Afterall this is just a .22lr and it is not a rifle we would be using in emergency or combat situations so if you have a problem with your primary sighting system just fix it. There is no need for two or three sighting systems on a .22lr

I have a quick release scope and a quick release reflex sight and can easily switch between the two, my iron sights have been put away in a box somewhere and I have never had a situation where I needed to use them because the scope was knocked out of true or the reflex sight's battery did not work but there probably are those out there who may have been in a situation where they had to have another back up system

ummm. what he said /\

[safearm]

I never had a problem with the Aimpoint, but I loaded up new batteries everytime I went outside the wire.

[bharrison913]

Thanks that has helped a lot

[Angel]

Originally Posted by safearm

I carried a M4 with Aimpoint in combat in Iraq.

What model Aimpoint did you use?
Thank you for your service.

[chuck s]

My first generation M68 COO. AKA Aimpoint CompM-XD (the Army bought none of the earlier Aimpoints to my knowledge) has functioned perfectly for over 10 years. Battery life is "only" 1000 hours or 41 days. If left on. If in doubt I'll change the battery.

I've never seriously considered buying a later model mainly because the 3MOA dot seems perfect for me and I no longer carry an M4 every day. Aimpoint just installed a new switch in it for me (under warranty).

Here's a breakdown of versions prior to the recent M4 version (from M4Carbine dot net):

There have been four verisons of Aimpoints released in the last 10 years that the military uses for combat units. I will explain the models from the oldest to the newest.

Late 80 to early 90s.
compM: 3MOA dot, two piece body, 100 hour battery life. Night vision model.
compML: 3MOA dot, two piece body, 100 hour battery life. Non NV model.

Mid 90s.
compM-XD: 3MOA dot, two piece body, 1000 hr battery life. Night vision model.
compML-XD: 3MOA dot, two piece body, 1000 hr battery life. Non NV model.


Notice the word comp has been dropped from the name.

Late 90s to 2004.
M2: 4MOA dot, one piece body, 10,000 hr battery life. Night vision model.
ML2: 4MOA dot, one piece body, 10,000 hr battery life. Non NV model.

Current production.
M3: 2 or 4MOA dot, one piece body, 50,000 hr battery life. Night vision model.
ML3: 2 or 4MOA dot, one piece body, 50,000 hr battery life. Non NV model.

All the above models are water proof to 66 feet IIRC. Some of the early models may not be. It's been a long time since I looked at the depth issue.

I hope this helps explain the differences in the units.

-- Chuck

[bgdv1]

Originally Posted by safearm

I carried a M4 with Aimpoint in combat in Iraq. We carried a lot of stuff with us, including extra batteries. In the heat of real battle, when real bad guys are shooting at you, it's a whole lot easier to flip up you BUIS and continue to engage, rather than change batteries.
We also marked the rear reticle of our Aimpoints with a magic marker dot. In daylight, you didn't need to turn it on, just use the back dot.
If you're at the range or shooting at targets that aren't shooting back, you can do away with iron sights and swap batteries.

the black dot sounds like a good idea. also my THANK YOU for your service, it is appreciated.

[sgtvilla]

Agree on all points about the advantages of co-witnessing. As a rule, my iron sights are my primary sighting system and I make sure I have the best zero possible and then co-witness my optics. If my optic breaks and I need to replace it, if I don't have time to go zero it at the range (happens all the time in Iraq), I can just get a different one on there and co-witness it. It may end up not being 100% zeroed, but pretty damn close. I have used M68s in the past, and carried an eotech on my first deployment in iraq. This method works like a charm.

In 2009 while at the national training center (NTC) with my unit, my grenadier's optic broke (he carried an M4 with an M203 grenade launcher attached to it). He had an M68 and it took a **** on him. We got another one the night before we had a live fire excercise. The problem was that his iron sights where not zeroed either.

I ended up fixing this problem for him by doing a mechanichal or battle zero on his iron sights and then cowitnessing the new optic (an eotech). He hit every target the next day without a problem (and thats with a mechanical zero which is not as accurate)