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How To Mount a Rifle Scope on an Ar-15

Although buying a scope is easy because there are many models on the market and some don’t cost too much, when using an AR 15, most people find it challenging to mount the scope.

If your AR 15 scope isn’t installed correctly, it won’t be of any use even if you buy the best one available.

To that end, we’ll be detailing the steps necessary to securely attach a rifle sight to an AR 15 rifle in this article. By following the instructions here, you will also make it less likely that you will make mistakes and more likely that you will end up with a perfectly mounted rifle sight. Keep reading!

Equipment Required for Scope Installation on an AR 15

The fundamentals of mounting a sight on an AR15 with a one-piece cantilever mount or a bolt-action rifle with standard bases and rings are the same. But before you get started, you’ll need a few basic tools to properly mount the riflescope. For eye relief, these tools are a necessity. You can use basic gear, but you risk ruining the optic if you do. Below are the best-recommended gears to mount a scope on an AR15. 

  • The Hex Bit Tool
The Hex Bit Tool

It is a handy mounting tool to have available because you can use it with other firearms besides only the AR 15. You may always get The Gun Tool from Real Avid if you don’t already have one. The device includes common bits and wrenches that are effective on weapons.

  • The Torque Wrench 

The torque wrench is an excellent tool to have on hand and is required for attaching the scope mount to the AR15 platform.

  • Cantilever Scope Mount 

This mount has two sets of rings that accommodate Picatinny rail and a rear extendable double ring.

  • Bubble Level 

You must use a bubble level when mounting a scope or gun sight because failing to do so will reduce shooting accuracy. When mounting the scope, ensure through the scope tube that the scope is perfectly level.

  • Cleaning Patches and Rubbing Alcohol 

Apply cleaning patches and rubbing alcohol to the mount, rail, screws, and other mounting gears to remove oil and grease.

Instructions for Mounting a Scope on an AR15 Rifle 

You can use the guidelines below to install your scope on an AR-15. Never forget to take your time and exercise patience throughout the entire process. If you’ve never mounted an optic on a rifle before, go slowly and aim precisely. 

Below are step-by-step instructions on the AR 15 scope mount. Read carefully!

  • Step One: Preparing the AR-15 for Scope Mounting 

Ensure your guns are empty by taking out the magazine. This is crucial in this situation. If you have a gun vice or shooting rest, hold the firearm in it to keep it safe. Inspect the rail, screws, and mount by wiping away any extra oil from the parts using a few of the cleaning patches and rubbing alcohol. Before you begin, set it using the bubble level to the appropriate level.

  • Step Two: Prepare to Attach the Scope Mount 

After you’ve leveled your AR 15 on the shooting rest, you can attach the scope mount to the top of the upper receiver. Never attach the mount to the upper receiver as well as the free-floating rail. If the scope tube is subjected to excessive strain, it could break.

First, use your hand to securely fasten the scope mount without over-tightening it. Utilize the torque wrench that came with the rifle scope mount to keep it in place, and read the instructions carefully.

You should not overtighten the scope mount, as the torque required varies depending on the type of rifle scope mount.

  • Step Three: Attach the Scope 

Simply attach the optic to the rifle when you have ensured the scope mount is stable. Ensure the rings rest flush against the optic’s flat surface when you set it onto the mount. Take the top of the rings and set it over the optic to fasten it in position. The rings fasten in an “X” pattern when the muscle is contracted.

Don’t snug them up completely just yet, and check that the gaps on both sides of the ring are the same size. Again, when the clamping of the scope rings is complete, there ought to be a slight gap capable of moving the optic.

Now is also a good time to adjust the eye relief on your scope to a comfortable magnification setting.

  • Step Four: It’s Time to Compare Everything 

On the smooth surface of the rifle tube, set the bubble level. These stages are simple if you do have the AR 15 in the shooting rest, but you must ensure that the weapon is level. Nevertheless, you must first level the reticle both vertically and horizontally before you level the sight. To achieve this, you can use your level to check the vertical alignment of a target or wall. After lining up the crosshair, check that the scopes are in alignment by placing the bubble level on top of the sight. Remember, eye relief is a primary factor to consider in this step.

  • Step Five: Planning to Complete 

When you have completed all of the aforementioned processes, you can secure the scope rings and use the “X” pattern to uniformly tighten the screws on both sides. Your AR 15 scope ought to be safe and operational by this point.

What Does “Lapping the Scope Rings” Mean?

If you need to attach a scope to your rifle, you should consider taking it to a gunsmith who specializes in lapping scope rings. Lapping refers to the process of smoothing the inner surfaces of the rings to achieve a uniform thickness. When done in this manner, the rings and the scope have the best possible contact area.

This is an important stage that should not be skipped if you intend to engage in long-range shooting at about 550 yards, especially when a red dot sight is to be used. However, scope ring lapping kits such as the ring screw are available on the market and they are not inexpensive if you only intend to use them once. Fortunately, a plethora of gunsmiths are willing to use the rings because of their fair prices.


Final Thoughts 

Putting a scope on your rifle may not be the most exciting part of getting ready for a day at the range, but it is crucial to your success. The rifle scope is just as good as its mount, no matter how much time and effort the optics team puts into finding ways to make them more robust and reliable. 

A shooter is guaranteed to have better night vision when his scope is properly mounted. When planning the purchase of a new optic, some shooters fail to account for the cost of a suitable mount, which ultimately diminishes their overall experience. 

Skilled shooters know how important it is to have a solid lockup between their optic and rifle, so they take the time to research the finest mount for their scope.  To accurately hit your target each time you shoot with your AR 15, ensure to follow the guidelines in this article.

2 thoughts on “How To Mount a Rifle Scope on an Ar-15”

  1. Thank you for informing us that lapping scope rings should not be skipped if we intend to use the rifle for long-range shooting since this process involves smoothing the inner surfaces of the rings for uniform thickness to ensure the rings and the scope get the best possible contact area. Speaking of scope rings, my brother recently invested in an AR-15, so he’s looking for scope rings to use on his new firearm soon. I’ll keep what you said in mind while I help him find the CZ scope rings he needs soon.

    1. Im glad to hear that. CZ scope rings can be a good choice for an AR-15, make sure they are the right size and height for the specific scope and firearm being used. If you or your brother have any other questions or need further assistance, feel free to ask.

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