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The Ultimate Guideline - How To Mount A Scope On An AR 15

The Ultimate Guideline - How To Mount A Scope On An AR 15
You already have your AR 15, so the next step is to improve the accuracy for long-range shooting by getting a AR 15 Riflescope.
However, while you may have the best riflescope, mounting it can seem like a huge undertaking. You have done all your research on caliber and shooting platforms.
You want to make certain the optic and bore is pointing in the same direction when you head out to the range. Alternatively, you do not want to end up with a misaligned scope and need to start over again.
Yes, we know it can be annoying to get the scope mounted flawlessly we are here to help with a step-by-step guide.
By following the guidelines provided it would help reduce the opportunity for error to mount your optic without troubles. 
Tools You Need to Mount a Scope on an AR 15
Whether you are using a one-piece cantilever mount on the AR or traditional bases and rings on bolt-action rifle to mount the scope, the basics remain the same. However, before you start, you will need some essential tools to fit the riflescope. You can use regular tools, but can damage the optic, and recommend the following:
  • The Hex Bit Tool is a useful tool to keep around as you can use it on different guns and not only the AR 15. If you do not have one you can always buy The Gun Tool from Real Avid. The gizmo comes with standard bits and wrenches that work well on firearms.
  • The Torque Wrench is necessary for fixing the scope mount to the AR15 platform and a great tool to have around.  
  • Cantilever Scope Mount the mount comes with a forward reach double ring and includes two sets of rings to fit Picatinny Weaver Rails.
  • Bubble Level for installing a scope or firearm sight you need a bubble level, as not using one will ruin the accuracy. You need to make sure the optic is entirely level when installing the scope.
  • Rubbing Alcohol & Cleaning Patches to clean all parts before mounting the scope.
  • Shooting Rest or Gun Vice spend some extra money and get yourself a shooting rest to place the rifle as it also helps to test the accuracy of the installed scope. You can find ones available at affordable prices to use with both rifles and handguns.
The majority of these tools you may already have around the house. You can skip the shooting rest, but it will make a massive difference with the mounting process. Once you have all your equipment together, look at the following steps here.

To mount your scope to the AR-15, you can follow the instructions below. Always remember not to rush it and be patient during the whole process. If you are new to mounting an optic to a rifle, take it slow and do it accurately. You do not want to get to the end and need to re-do the whole process again.
First Step – Preparing the AR-15 for Scope Mounting
Here the important thing is to make sure your rifles unloaded by removing the magazine. Place the gun in the shooting rest or gun vice if you have one to make it secure. Take some of the cleaning patches and rubbing alcohol and clean the rail, screws, and mount by removing excess oil from the components. Use the bubble level to get it at the right level setting before you start.
Second Step – Get Ready to Add the Scope Mount
With the AR 15 placed level in the shooting rest, take the scope mount and put it on top of the upper receiver. Avoid placing the mount on both the free-floating rail and upper receiver. By doing, this, it can cause unwanted stress on the tube.
Now tighten the scope mount with your hand by making it stable and not too tight. Take the torque wrench to tighten the mount and pay close attention to the instructions provides with the scope mount.
Each scope mount has a different torque level, and you do not want to over-tighten it.
Third Step – Add the Scope
Once you have the scope mount, secure it is time to fix the optic on your rifle. Drop the optic onto the mount and make sure the rings sit on the flat surface of the scope. Now take the top portion of the rings and place it over the optic to secure. When you tighten, the rinds do it in an “X” pattern.
Do not fully tighten them yet and make sure that each side of the ring when tightening has the same gap level. Once the tightening of the scope rings done, there should be a small gap available to move the optic.
At this time of the process, you can also check the scopes eye relief to find a suitable position for you.
Fourth Step – Time to level everything
Place the bubble level on the flat part of the rifle tube. If you have the AR 15 in the shooting rest, this steps easy, but you must make sure the rifle is level. However, before you level the scope, you need to align the reticle horizontally and vertically. You can do this by looking at a target or doorframe vertically verified with your level. Once aligning the crosshair place the bubble level on top of the optic to make sure the scopes aligned as well.
Fifth Step – Finishing Up
Once following all the above steps, you can tighten the scope rings and make use of the “X” pattern to tighten the screws evenly on both sides. Now your AR 15 scope should be secure and ready to use.
What is Lapping the Scope Rings?
A gunsmith does lapping of scope rings when you take your rifle to mount a scope. Lapping is the sanding down of the rings on the inside to make them even. By doing this, it gives the best surface-to-surface between the rings and the scope. The process is not included in the steps for one reason you can easily do it wrong and ruin the rings.
If you do plan to do long-range shooting at 600-yards, this is a crucial step, and one should not ignore it. You can buy a scope ring lapping kit, but they are not cheap if you only plan to use it once. Luckily, many gunsmiths offer this service at a reasonable price.
Final Thoughts
We hope you found the guidelines helpful to mount a scope on your AR 15 successfully. The important thing is to keep the weapon and optic level.
For the best advice, we recommend you over check everything with the bubble level during the whole process.
As the saying goes, it is better to be safe than ending up sorry and need to start all over. By following the steps, you can make the mounting simpler to begin shooting your rifle at the range.
A small note is if you want to shoot at long distances take your rifle and scope to a professional gunsmith. They will do the scope ring lapping for you. By doing this, it provides more accuracy and makes the optic work properly while prolonging the service.