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How To Set Up Co-Witness Sights

How To Set Up Co-Witness Sights

April 10, 2019

When it comes to outfitting your AR-15, you’re always looking for the latest and greatest accessories. Naturally, that includes red dot and laser sights. These sights are becoming increasingly popular on sporting rifles of all varieties, and are praised for the ease of use, accuracy, and speed of target acquisition. However, they aren’t a perfect product and have their own faults. When your red dot or laser sight fails, it’s important that you have another way to aim your rifle. This is where a set of BUIS, or back up iron sights, comes into play.

But slapping two sighting systems onto a rifle doesn’t necessarily mean you’ll be more accurate. These two systems have to work together, and that’s why it’s important to co-witness your sights. Don’t know what we’re talking about? Don’t panic, RailScales is here to help. We’ll outline how you can set up co-witness sights on your AR-15.

What is Co-Witness?

On many rifle setups, you’ll find a pair of fixed iron sights and a scope, red dot, or laser. When these two kinds of sights are lined up, this is co-witnessing. Essentially, when they are properly set up and zeroed, the two sets of sights work together. The red dot will actually rest on top of your iron sights.

Why It’s Important To Co-Witness Your Sights

Whether you’re on the range or in a self-defense situation, the last thing you want to think about is, “Did I change the battery on my optic?” When your red dot or reflex sight suddenly fails, either due to battery issues or damage, you’ll need another way to reliably aim your rifle. Without back up sights, you’re effectively guessing at where your rounds are going, which is a dangerous and ineffective way to shoot.

However, if you have a set of back up iron sights that are co-witnessed with your optic, you can quickly switch from optic to irons. This offers an uninterrupted sight picture and maintains your focus on your target.

Which Co-Witness Works Best?

So we know what it is, and now we know why you should do it, so how do you do it? Fortunately, it’s a fairly straightforward process. The hiccup, of course, is choosing which kind of co-witness is best for you and your rifle.

Absolute Co-Witness

An absolute co-witness set up is when the reticle from the red dot is resting right on top of your front sight post. This means that your sights are always lined up, so if your optic suddenly shuts off, you don’t lose track of where you were aiming. Additionally, this set up works great when you’re transitioning from a dark to a light space so that you don’t lose focus even as your red dot gets washed out. The downside is that your sight picture through your optic can be cluttered, making it hard to visualize a target completely. This co-witness set up is best for those with flip up iron sights.

⅓ Co-Witness

Having a ⅓ co-witness sight set up is just as it sounds. In this set up your BUIS will be in the lower third of your optic. The red dot seems to hover above the top of the front sight. This offers you a wider field of view through the optic. If you find the front sight post distracting when you use a red dot, this is a great set up for you. Should the red dot fail, you simply shift your head, line up your iron sights, and continue shooting. However, having the sights at different heights requires you to change how you position your head and neck, which can cause strains if you’re not used to shooting from that position. This co-witness set up is best for those with fixed iron sights.

Setting Up Co-Witness Sights On Your AR-15

Co-witnessing your sights is actually simpler than you might first realize. When set up properly, you can seamlessly shift from your digital optic to your iron sights and back again. When setting up your co-witness, follow these steps:

Put Iron Sights On Your Rifle

More and more manufacturers are selling rifles that have a million attachment points for optics and sights, but no actual sights. You’ll want to make sure you have iron sights you can use. Many now offer flip up iron sights that can be attached to your rails quickly. You can also get fixed iron sights for your front sight post, and make use of a flip up sight for the rear. If you have a laser sight module, you can even mount a front sight post directly to the module itself with our LEAF front sight.

Zero Your Iron Sights

Your co-witness will be useless if your iron sights aren’t properly zeroed. Make sure they are zeroed at the range you usually shoot at, and make any adjustments now before you add an optic.

Mount Your Optic

Place your optic, like a red dot or reflex sight, on your rifle. Make sure that you can clearly see your front sight post through your optic. In some cases, you might need a riser for your iron sights, or your optic to make sure that both can be seen clearly.

Once it’s in a comfortable position for you, you’ll need to adjust the reticle until it is in line with your iron sights. This can be tricky if you’re juggling the rifle while you’re adjusting the optic. You might consider using a bipod, lead sled, or sandbags while you work.

Finally, test fire a few rounds with the optic to make sure it’s zeroed along with your iron sights.

Iron Sights For Your AR-15

When space is at a premium on your AR-15, you have to get creative in how you mount your sights. That’s why RailScales offers our LEAF iron sights. Designed for ATPIAL series and D-Bal & PEQ15 lasers, the LEAF eliminates the need for a dedicated front sight. Instead, it’s mounted directly to the laser itself. This saves space and weight, both of which are at a premium on your rifle.

Order your high-end AR-15 accessories now.