Co-Witnessing is the ability to use your iron sights in coordination with a red dot or a holographic optic. The point of co-witnessing is to allow users a BUIS, also known as back up iron sights.
Anytime you attach electronics to your rifle you run the risk of them failing, and anytime you run an optic on your weapon you run the risk of it failing. An optic that relies on electronics to function can be a devastating loss in a combat, self defense, hunting, or competition should the optic fail.
It’s critical to know how to co-witness when you are running an electronic, non magnified optic. If you have a proper co witness sight you can transition seamlessly from your optic to your back up iron sights. This allows shooter to continue with their chosen objective with hardly a second lost. Another advantage is the ability to use iron sights to make precise shots at close range. Iron sights, well good iron sights, are going to be more accurate and more precise when used appropriately.
You can also use iron sights to avoid running into parallax with your red dot or holographic sight. Parallax isn’t a huge concern if you are engaging large targets, like man sized targets. For small targets, like shotgun hulls, parallax can have an effect, iron sights do not suffer from parallax.
3 Simple Steps To Follow
1. The first step is to actually have iron sights. Way too many rifles these days are coming from the factory in a sight free configuration, this isn’t just cheaper, or budget minded ARs, but my SIG 556R came without irons. So have iron sights.
Most optics, or the ones we recommend in our buying guide, are designed to co witness with AR 15 height sights, and since this is the most popular rifle in the United States, this is probably the rifle you have. On a standard A4/A3 upper a fixed front sight and a standard height rear sight like those from Magpul or Yankee Hill will align with nearly every red dot and holographic sight on the market. If you use non standard iron sights or an optic that doesn’t co witness you’ll need a riser or spacer.
Many optics will also have the option of a rise or spacer to raise your sights to AR sight levels, or lower then to co witness with other rifles. For example my Aimpoint T1 can co witness with my AK sights in its stock configuration. For different rifles you’ll have to experiment with the height of your sights, and the height of your optic.
2. Once you have the iron sights, optic, and the spacer/riser if necessary you’ll move to zeroing your iron sights. Iron sights should be zeroed first. Once you zero your iron sights and you have confirmed and are comfortable with their zero you can mount your optic.
3. Once the optic is mounted you’ll need to adjust the reticle until it is in line with your iron sights.
You’ll need to behind your rifle looking down the sights to align the dot with the iron. This is where a bipod, sandbags or a lead sled can come in handy. Once the sight is aligned you need to confirm the zero with just the optic. This means you need to replicate the same shooting position, shoot style, range, and ammunition you used for your iron sight zero. The reticle on your red dot or holographic optic should match your iron sights.
That Is All Folks
So preparing your weapon and optic to run in coordination with iron sights is rather easy. The importance is that it is done correctly. You’ll be depending on your iron sights and there is no reason to remove them, so leave them in place. You’re now set up to co witness with your iron sights. It’s important to maintain your skills with iron sights, so practice with irons occasionally, and maintain your skills. Co-witnessing doesn’t matter if you can’t shoot with iron sights.